diff --git a/backend/static/js/codemirror/modes/sparql/sparql-hint.js b/backend/static/js/codemirror/modes/sparql/sparql-hint.js
index 69afefe2..6755c17f 100755
--- a/backend/static/js/codemirror/modes/sparql/sparql-hint.js
+++ b/backend/static/js/codemirror/modes/sparql/sparql-hint.js
@@ -5,14 +5,13 @@ var size = 40; // size for next auto completion call
 var resultSize = 0; // result size for counter badge
 var lastWidget = undefined; // last auto completion widget instance
 var activeLine; // the current active line that holds loader / counter badge
-var activeLineBadgeLine; // the bade holder in the current active line
+var activeLineBadgeLine; // the badge holder in the current active line
 var activeLineNumber; // the line number of the active line (replaced by loader)
 
 var sparqlCallback;
 var sparqlFrom;
 var sparqlTo;
 var sparqlTimeout;
-var sparqlRequest;
 var suggestions;
 
 (function (mod) {
@@ -148,30 +147,35 @@ var suggestions;
 
   }
 
+  // This function defines the CORE LOGIC OF THE QLEVER UI SUGGESTIONS
+  //
+  // TODO: explain how it works in this comment.
   CodeMirror.registerHelper("hint", "sparql", function (editor, callback, options) {
 
-
-    // ************************************************************************************
-    //
-    //
-    //                        CORE LOGIC OF QLEVER UI SUGGESTIONS
+    // If a previous AC query is still running, cancel it.
     //
-    //
-    // ************************************************************************************
-
-    // skip everything that is running by now
+    // NOTE: `sparqlTimeout` and `activeLine` are both set in the function
+    // `getQleverSuggestions` (which sends the AC query to the backend and turns
+    // the result into nice-looking suggestions).
     window.clearTimeout(sparqlTimeout);
-    if (sparqlRequest) { sparqlRequest.abort(); }
-
-    // reset the previous loader
     if (activeLine) {
       activeLine.html(activeLineNumber);
     }
 
-    var cur = editor.getCursor(); // current cursor position
-    var absolutePosition = editor.indexFromPos((cur)); // absolute cursor position in text
-    var context = getCurrentContext(absolutePosition); // get current context
-    suggestions = [];
+    // Get the current cursor position and its index in the whole query.
+    var cur = editor.getCursor();
+    var absolutePosition = editor.indexFromPos((cur));
+
+    // Get the element of the query tree at that position.
+    //
+    // TODO: This is currently a major bug, since for a typical SPARQL query,
+    // there are different tree elements for ordinary triples, the FILTER
+    // clauses (one element each), or the UNION or OPTIONAL clauses (again, one
+    // element each). That way, the sensitive AC queries do not work correctly
+    // when one of FILTER, UNION, or OPTIONAL is present, or after these
+    // clauses.
+    var context = getCurrentContext(absolutePosition);
+    // console.log("context", context);
 
     log('Position: ' + absolutePosition, 'suggestions');
     if (context) {
@@ -180,7 +184,7 @@ var suggestions;
       log('Context: None', 'suggestions');
     }
 
-    // get current token
+    // Get the token at the current cursor position.
     var line = editor.getLine(cur.line).slice(0, cur.ch);
     var token = getLastLineToken(line);
     var start, end;
@@ -189,15 +193,19 @@ var suggestions;
     } else {
       start = token.start;
       end = token.end;
-
     }
 
+    // Determine all types that potentially could (not necessarily actually do)
+    // occur in this context. These are all `TYPES` which contain the name of
+    // the current context in their `availableInContext`.
     types = getAvailableTypes(context);
+    // console.log("Types: ", types);
 
     sparqlCallback = callback;
     sparqlFrom = Pos(cur.line, start);
     sparqlTo = Pos(cur.line, end);
 
+    suggestions = []; // TODO: Why is this a global variable?
     var allTypeSuggestions = [];
     for (var i = 0; i < types.length; i++) {
       for (var suggestion of getTypeSuggestions(types[i], context)) {
@@ -236,10 +244,12 @@ function getAvailableTypes(context) {
   if (context) {
     contextName = context.w3name;
   }
+  // console.log(`getAvailableTypes -> contextName: ${contextName}`);
 
   // check for complex types that are valid in this context
   for (var i = 0; i < COMPLEXTYPES.length; i++) {
     if (COMPLEXTYPES[i].availableInContext.indexOf(contextName) != -1) {
+      // console.log(`getAvailableTypes -> type: ${COMPLEXTYPES[i].name}`);
       types.push(COMPLEXTYPES[i]);
     }
   }
@@ -268,6 +278,10 @@ function detectPropertyPath(predicate) {
   return propertyPath;
 }
 
+// Get suggestions for the given "context" (element of the query tree).
+//
+// NOTE: This function is only called via the `TRIPLE` type in `COMPLEXTYPES`
+// from `sparql.js`. It eventually calls `getQleverSuggestions`.
 function getDynamicSuggestions(context) {
   var cur = editor.getCursor();
   var line = editor.getLine(cur.line);
@@ -276,10 +290,10 @@ function getDynamicSuggestions(context) {
   word = getLastLineToken(line.slice(0, cur.ch));
   if (word.endsInWhitespace) { word = ""; } else { word = word.string; }
 
-  // get current line
+  // Get current line and split into `words` by whitespace.
   var words = line.slice(0, cur.ch).trimLeft().replace('  ', ' ').split(" ");
 
-  // Find words that are separated by whitespace but seem to be belong together
+  // Find words that are separated by whitespace but seem to belong together.
   var whiteSpaceWord = "";
   for (var i = words.length - 1; i >= 0; i--) {
     var prevWord = words[i]
@@ -317,6 +331,7 @@ function getDynamicSuggestions(context) {
 
   // Get editor lines and remove current line.
   var lines = context['content'].split('\n');
+  // console.log("lines", lines);
   for (var i = 0; i < lines.length; i++) {
     if (lines[i] == line) {
       lines.splice(i, 1);
@@ -358,7 +373,11 @@ function getDynamicSuggestions(context) {
 
   } else {
 
-    // find connected lines in given select clause
+    // Find part of query to plug in for %CONNECTED_TRIPLES% in AC query
+    // templates.
+    //
+    // TODO: Lines with FILTER on connected variables are missing,
+    // for example https://qlever.cs.uni-freiburg.de/wikidata/Z0FvRA
     const variableRegex = /\?\w+\b/g;
     let seenVariables = line.match(variableRegex);
     if (seenVariables) {
@@ -428,15 +447,23 @@ function getDynamicSuggestions(context) {
         }
         mode1Query = SUGGESTPREDICATES_CONTEXT_INSENSITIVE;
         mode2Query = SUGGESTPREDICATES;
-        
       } else if (words.length == 3) {
         predicateForObject = words[1];
         suggestVariables = "normal";
         appendToSuggestions = ' .';
         nameList = objectNames;
-        mode1Query = SUGGESTOBJECTS_CONTEXT_INSENSITIVE;
+        // TRYING STH OUT: Make object AC queries "half-sensitive" (ignore the
+        // context triples, but not the predicate, see head.html). If you want
+        // to restrict this to certain instances, use a condition like SLUG ==
+        // "pubchem".
+        if (SLUG != "uniprot") {
+          mode1Query = SUGGESTOBJECTS_CONTEXT_HALFSENSITIVE;
+        } else {
+          mode1Query = SUGGESTOBJECTS_CONTEXT_INSENSITIVE;
+        }
         mode2Query = SUGGESTOBJECTS;
-        // replace the prefixes
+
+        // Replace the prefixes.
         var propertyPath = detectPropertyPath(words[1]);
 
         for (var i in propertyPath) {
@@ -486,7 +513,10 @@ function getDynamicSuggestions(context) {
           var subjectVarName = subject.split(/[.\/\#:]/g).slice(-1)[0].replace(/@\w*$/, '').replace(/\s/g, '_').replace(/[^a-zA-Z0-9_]/g, '').toLowerCase();
           var objectVarName = lastWord.split(/[.\/\#:]/g).slice(-1)[0]
             .replace(/@\w*$/, "").replace(/\s/g, "_")
-            .replace(/^has([A-Z_-])/, "$1$").replace(/[^a-zA-Z0-9_]/g, "").toLowerCase();
+            .replace(/^has([A-Z_-])/, "$1$")
+            .replace(/^([a-z]+)edBy/, "$1$")
+            .replace(/^(year)[A-Z_]\w*/, "$1$")
+            .replace(/[^a-zA-Z0-9_]/g, "").toLowerCase();
 
           response.push('?' + objectVarName + ' .');
           response.push('?' + subjectVarName + '_' + objectVarName + ' .');
@@ -684,22 +714,33 @@ function parseAndEvaluateCondition(condition, word, lines, words) {
   return conditionSatisfied;
 }
 
+// Get result of SPARQL query with timeout.
+//
+// NOTE: The function returns immediately with a `fetch` promise. To wait for
+// the result of the `fetch` (or its failure), call `await fetchTimeout(...)`.
+//
+// TODO: Better use QLever's timeout, so that the query no longer burdens the
+// backend after the timeout. This would have the drawback that the code would
+// then only work for SPARQL enpoints supporting a "timeout" argument. Note that
+// Virtuoso does have such an argument, too, but the unit is milliseconds and not
+// seconds like for QLever.
 const fetchTimeout = (sparqlQuery, timeoutSeconds, { ...options } = {}) => {
-  const ms = timeoutSeconds * 1000;
+  const timeoutMilliseconds = timeoutSeconds * 1000;
   const controller = new AbortController();
+  // `BASEURL` is defined in backend/templates/partials/head.html . It's the
+  // base URL from the backend configuration.
   const promise = fetch(BASEURL, {
-    // BASEURL + "?query=" + encodeURIComponent(sparqlQuery), {
     method: "POST",
     body: sparqlQuery,
     signal: controller.signal,
-    headers: { 
+    headers: {
       "Content-type": "application/sparql-query",
       "Accept": "application/qlever-results+json"
     },
     ...options
   });
-  if (ms > 0) {
-    const timeout = setTimeout(() => controller.abort(), ms);
+  if (timeoutMilliseconds > 0) {
+    const timeout = setTimeout(() => controller.abort(), timeoutMilliseconds);
     return promise.finally(() => clearTimeout(timeout));
   } else {
     return promise;
@@ -728,16 +769,21 @@ function getSuggestionsSparqlQuery(sparqlQuery) {
     + sparqlQuery.replace(/^PREFIX.*/mg, ""), "requests");
 
   return sparqlQuery;
-  // let url = BASEURL + "?query=" + encodeURIComponent(sparqlQuery);
-  // return url;
 }
 
 
-function getQleverSuggestions(sparqlQuery, prefixesRelation, appendix, nameList, predicateForObject, word, mixedModeQuery) {
-  /* mixedModeQuery is the case-insensitive query that is sent additionally to the case-sensitive query when mixed mode is enabled. */
+// Get suggestions from QLever backend and show them to the user.
+function getQleverSuggestions(
+  sparqlQuery,          // the main AC query
+  prefixes,             // prefixes used for abbreviating IRIs
+  appendix,
+  nameList,
+  predicateForObject,
+  word,
+  mixedModeQuery        // `mixedModeQuery` : the "backup" query when in mixed mode
+) {
 
-
-  // show the loading indicator and badge
+  // Show the loading indicator and badge
   activeLineBadgeLine = $('.CodeMirror-activeline-background');
   activeLine = $('.CodeMirror-activeline-gutter .CodeMirror-gutter-elt');
   activeLineNumber = activeLine.html();
@@ -749,33 +795,42 @@ function getQleverSuggestions(sparqlQuery, prefixesRelation, appendix, nameList,
   const mixedModeSparqlQuery = getSuggestionsSparqlQuery(mixedModeQuery);
   var dynamicSuggestions = [];
 
+  // The actual code for getting the suggestions and showing them.
+  //
+  // TODO: Why is this wrapped in a `setTimeout` with a timeout of only 500
+  // milliseconds?
+  const sparqlTimeoutDuration = 500;
   sparqlTimeout = window.setTimeout(async function () {
+    // Issue AC query (or two when in mixed mode) and get `response`.
     try {
+      // When in mixed mode, first issue the alternative query (but don't wait
+      // for it to return, `fetchTimeout` returns a promise).
       let mixedModeQuery;
       if (mixedModeSparqlQuery) {
-        mixedModeQuery = fetchTimeout(mixedModeSparqlQuery, DEFAULT_TIMEOUT);  // start the mixed mode query, but async
+        mixedModeQuery = fetchTimeout(mixedModeSparqlQuery, DEFAULT_TIMEOUT);
       }
+      // Issue the main autocompletion query (and wait for it to return).
       const mainQueryTimeout = mixedModeSparqlQuery ? MIXED_MODE_TIMEOUT : DEFAULT_TIMEOUT;
       let response;
       let mainQueryHasTimedOut = false;
-      let showTimeoutError = false;
+      let allQueriesHaveTimedOut = false;
       try {
-        response = await fetchTimeout(lastSparqlQuery, mainQueryTimeout);  // start the main query and wait for it to return
+        response = await fetchTimeout(lastSparqlQuery, mainQueryTimeout);
       } catch (error) {
         if (error.name === "AbortError") {
           mainQueryHasTimedOut = true;
-          showTimeoutError = true;
+          allQueriesHaveTimedOut = true;
         } else {
           throw error;
         }
       }
+      // If the main query timed out (or failed for other reasons), and we are
+      // in mixed mode, take the result of the alternative query.
       if (mainQueryHasTimedOut && mixedModeSparqlQuery) {
-        // the main query timed out.
-        // get the mixedModeQuery's response and continue with that
         log("The main query timed out. Using the context-insensitive suggestions.", 'requests')
         try {
           response = await mixedModeQuery;
-          showTimeoutError = false;
+          allQueriesHaveTimedOut = false;
         } catch (error) {
           if (error.name !== "AbortError") {
             throw error;
@@ -783,14 +838,20 @@ function getQleverSuggestions(sparqlQuery, prefixesRelation, appendix, nameList,
         }
       }
 
+      // Get the actual query result as `data`.
       let data;
-      if (showTimeoutError) {
+      if (allQueriesHaveTimedOut) {
         data = {exception: "The request was cancelled due to timeout"};
       } else {
         data = await response.json();
       }
 
-      
+      // Show the suggestions to the user.
+      //
+      // NOTE: This involves some post-processing (for example, showing the
+      // suggestions with prefixes like `wdt:` and not with their full IRIs as
+      // returned by the backend) and several hacks (for example, when wdt:P31
+      // is a suggestion, also add wdt:P31/wdt:P279*).
       if (data.res) {
         log("Got suggestions from QLever.", 'other');
         log("Query took " + data.time.total + " and found " + data.resultsize + " lines", 'requests');
@@ -818,15 +879,18 @@ function getQleverSuggestions(sparqlQuery, prefixesRelation, appendix, nameList,
             }
           }
 
-          // add back the prefixes
+          // Abbreviate IRIs using the prefixes of the SPARQL query.
           var replacePrefix = "";
           var prefixName = "";
-          for (var prefix in prefixesRelation) {
-            if (entity.indexOf(prefixesRelation[prefix]) > 0 && prefixesRelation[prefix].length > replacePrefix.length) {
-              replacePrefix = prefixesRelation[prefix];
+          for (var prefix in prefixes) {
+            if (entity.indexOf(prefixes[prefix]) > 0 && prefixes[prefix].length > replacePrefix.length) {
+              replacePrefix = prefixes[prefix];
               prefixName = prefix;
             }
           }
+
+          // Repeat, using ALL prefixes from the backend configuraion
+          // (`FILLPREFIXES` is `fillPrefixes` from the backend configuration).
           if (FILLPREFIXES) {
             for (var prefix in COLLECTEDPREFIXES) {
               if (entity.indexOf(COLLECTEDPREFIXES[prefix]) > 0 && COLLECTEDPREFIXES[prefix].length > replacePrefix.length) {
@@ -847,7 +911,6 @@ function getQleverSuggestions(sparqlQuery, prefixesRelation, appendix, nameList,
             }
           }
 
-          // console.log("URL: " + window.location);
           var nameIndex = data.selected.indexOf(SUGGESTIONNAMEVARIABLE);
           var altNameIndex = data.selected.indexOf(SUGGESTIONALTNAMEVARIABLE);
           var entityName = (nameIndex != -1) ? result[nameIndex] : "";
@@ -919,11 +982,11 @@ function getQleverSuggestions(sparqlQuery, prefixesRelation, appendix, nameList,
         $('#suggestionErrorBlock').html('<strong>Error while collecting suggestions:</strong><br><pre>' + data.exception + '</pre>')
         console.error(data.exception);
       }
-      // reset loading indicator
-      
+
+      // Reset loading indicator.
       $('#aBadge').remove();
 
-      // add badge
+      // Add badge that shows the total numbers of suggestions.
       if (data.resultsize != undefined && data.resultsize != null) {
         resultSize = data.resultsize;
         activeLineBadgeLine.prepend('<span class="badge badge-success pull-right" id="aBadge">' + data.resultsize + '</span>');
@@ -945,17 +1008,26 @@ function getQleverSuggestions(sparqlQuery, prefixesRelation, appendix, nameList,
       return [];
     }
 
-  }, 500);
+  }, sparqlTimeoutDuration);
 
 
 }
 
 
-/**
- 
-Returns the suggestions defined for a given complex type
- 
-**/
+// Get all suggestions for the given `type`by computing the cross-product of the
+// elements in the array `type.suggestions`, see `COMPLEXTYPES` in `sparql.js`.
+//
+// For example, for the type `LIMIT`, the suggestion array is ['LIMIT ', [1, 10,
+// 100, 1000], '\n'], and the list of suggestions computed is hence
+//
+// LIMIT 1
+// LIMIT 10
+// LIMIT 100
+// LIMIT 1000
+//
+// An element of `type.suggestions` can also be a function. For example,
+// `TRIPLE` contains `function (c) { return getDynamicSuggestions(c); }`. These
+// functions are called with the given `context`.
 function getTypeSuggestions(type, context) {
 
   typeSuggestions = []
@@ -1043,11 +1115,16 @@ function getTypeSuggestions(type, context) {
   return typeSuggestions;
 }
 
-/**
- 
-Build a query tree
- 
-**/
+// Compute tree representation of the given (partial) SPARQL query.
+//
+// NOTE: The result is returned as an array of elements with fields `w3name`,
+// `content`, `start`, `end`, and optionally `children` (the latter giving this
+// a tree-like structure)giving this a tree-like structure). The values for
+// the fields `start` and `end` are absolute and not relative to the second
+// argument `start` of the function.
+//
+// NOTE: To get the tree for the whole query from the editor window,
+// call `buildQueryTree(editor.getValue(), 0)`.
 function buildQueryTree(content, start) {
 
   var tree = [];
@@ -1056,134 +1133,125 @@ function buildQueryTree(content, start) {
   var tempString = "";
   var tempElement = { w3name: 'PrefixDecl', start: start }
 
+  // Iteratively go through the query character by character.
   while (i < content.length) {
     tempString += content[i];
 
+    // Determine whether we should start a new tree element (`tempElement`) and
+    // finish the previous one. The following sequences (minus the quotes)
+    // start a new element:
+    //
+    // "SELECT ", "WHERE {", "OPTIONAL {",
+    //
+    // TODO: A lot of code duplication here and some mistakes. Also, why are the
+    // regexes hard-coded here and not part of the definitions of `CONTEXTS` in
+    // `sparql.js`?
     if (/SELECT $/i.test(tempString)) {
-
-      // shorten the end of prefix decl by what we needed to add to match SELECT 
       tempElement['content'] = tempString.slice(0, tempString.length - 7);
       tempElement['end'] = i + start - 6;
       tree.push(tempElement);
       tempString = "";
-
       tempElement = { w3name: 'SelectClause', suggestInSameLine: true, start: i + start }
-
     } else if (/WHERE \{$/i.test(tempString)) {
-
-      // shorten the end of the select clause by what we needed to add to match WHERE {
       tempElement['content'] = tempString.slice(0, tempString.length - 7);
       tempElement['end'] = i + start - 6;
       tree.push(tempElement);
       tempString = "";
-
       tempElement = { w3name: 'WhereClause', suggestInSameLine: true, start: i + start }
-
     } else if (/OPTIONAL \{$/i.test(tempString)) {
-
-      // shorten the end of the previous clause by what we needed to add to match OPTIONAL {
-      tempElement['content'] = tempString.slice(0, tempString.length - 7);
-      tempElement['end'] = i + start - 3;
+      tempElement['content'] = tempString.slice(0, tempString.length - 10);
+      tempElement['end'] = i + start - 9;
       tree.push(tempElement);
       tempString = "";
-
       tempElement = { w3name: 'WhereClause', suggestInSameLine: true, start: i + start }
-
     } else if (/MINUS \{$/i.test(tempString)) {
-
-      // shorten the end of the previous clause by what we needed to add to match OPTIONAL {
-      tempElement['content'] = tempString.slice(0, tempString.length - 4);
-      tempElement['end'] = i + start - 3;
+      tempElement['content'] = tempString.slice(0, tempString.length - 7);
+      tempElement['end'] = i + start - 6;
       tree.push(tempElement);
       tempString = "";
-
       tempElement = { w3name: 'WhereClause', suggestInSameLine: true, start: i + start }
-
-    } else if (/VALUES \(?$/i.test(tempString)) {
-
-      // shorten the end of the previous clause by what we needed to add to match VALUES {
-      tempElement['content'] = tempString.slice(0, tempString.length - 7);
-      tempElement['end'] = i + start - 6;
+    } else if (/VALUES $/i.test(tempString)) {
+      tempElement['content'] = tempString.slice(0, tempString.length - 8);
+      tempElement['end'] = i + start - 7;
       tree.push(tempElement);
       tempString = "";
-
       tempElement = { w3name: 'ValuesClause', suggestInSameLine: true, start: i + start }
-
-    } else if (/FILTER \(?$/i.test(tempString)) {
-
-      // shorten the end of the previous clause by what we needed to add to match VALUES {
+    } else if (/FILTER $/i.test(tempString)) {
+    // } else if (/FILTER \(?$/i.test(tempString)) {
       tempElement['content'] = tempString.slice(0, tempString.length - 7);
       tempElement['end'] = i + start - 6;
       tree.push(tempElement);
       tempString = "";
-
       tempElement = { w3name: 'Filter', suggestInSameLine: true, start: i + start }
-
     } else if (tempElement.w3name == 'ValuesClause' && /{$/i.test(tempString)) {
-
-      // shorten the end of the previous clause by what we needed to add to match VALUES {
+      // TODO: How does this go together with the regex for VALUES above?
       tempElement['content'] = tempString.slice(0, tempString.length - 7);
       tempElement['end'] = i + start;
       tree.push(tempElement);
       tempString = "";
-
       tempElement = { w3name: 'DataBlock', suggestInSameLine: true, start: i + start }
-
     } else if (/UNION \{$/i.test(tempString)) {
-
-      // shorten the end of the previous clause by what we needed to add to match UNION {
       tempElement['content'] = tempString.slice(0, tempString.length - 7);
       tempElement['end'] = i + start - 6;
       tempElement.w3name = 'WhereClause';
       tree.push(tempElement);
       tempString = "";
-
       tempElement = { w3name: 'WhereClause', suggestInSameLine: true, start: i + start }
-
     } else if (tempString.endsWith('{')) {
 
-      // fast forward recursion
+      // Iterate to find the closing `}` or the end of `content`. Extend
+      // `tempString` until before the closing `}`, while `subString` is the
+      // part after the opening `{`.
       var depth = 1;
       var subStart = i;
       var subString = "";
-      while (depth != 0 && i <= content.length) {
-        i++;
+      i++;
+      while (i < content.length) { // NOTE: was <= content.length and i++ at beginning.
         if (content[i] == '}') {
           depth -= 1;
+          if (depth == 0) break;
         } else if (content[i] == '{') {
           depth += 1;
         }
-        if (depth != 0) {
-          subString += content[i];
-          tempString += content[i];
-        }
+        subString += content[i];
+        tempString += content[i];
+        i++;
       }
 
+      // Recursively build tree for the part in "{...}".
       if (tempElement['children']) {
         tempElement['children'] = tempElement['children'].concat(buildQueryTree(subString, subStart));
       } else {
         tempElement['children'] = buildQueryTree(subString, subStart);
       }
-
-    } else if (tempString.endsWith('}') || ((tempElement.w3name == "OrderCondition" || tempElement.w3name == "GroupCondition") && tempString.endsWith('\n'))) {
-
-      // shorten the whereclause by what we needed to add to match the }
+    }
+    // Solution modifiers at the end of the query.
+    else if (tempString.endsWith('}') || ((tempElement.w3name == "OrderCondition" || tempElement.w3name == "GroupCondition") && tempString.endsWith('\n'))) {
       tempElement['content'] = tempString.slice(0, tempString.length - 1);
       tempElement['end'] = i + start - 1;
       tree.push(tempElement);
       tempString = "";
-
       tempElement = { w3name: 'SolutionModifier', suggestInSameLine: true, start: i + start }
-
     }
 
+    // Go to the next character.
     i++;
   }
 
+  // Add the last element.
   tempElement['content'] = tempString;
   tempElement['end'] = content.length + start;
   tree.push(tempElement);
 
+  // Some post-processing for `OptionalClause`, `UnionClause`, and
+  // `SolutionModifier`.
+  //
+  // TODO: Why do we need to explicitly set the name of the first child of
+  // `OptionalClause` and `UnionClause` to `WhereClause`?
+  //
+  // TODO: Why the additional parsing of the `SolutionModifier` here? Is it
+  // because we have additional structure within a line here, whereas the code
+  // above assumes that new elements only start at new lines?
   for (var element of tree) {
     if (element.w3name == "OptionalClause" || element.w3name == "UnionClause") {
       if (element['children']) {
@@ -1252,33 +1320,35 @@ function printQueryTree(tree, absPosition, prefix) {
   return logString;
 }
 
-/**
- 
-Returns the current context
- 
-@params absPosition - absolute position in text
- 
-**/
+// Get the context (see `CONTEXTS` from sparql.js) of the given
+// position.
 function getCurrentContext(absPosition) {
   var tree = buildQueryTree(editor.getValue(), 0);
   log("\n" + printQueryTree(tree, absPosition, ""), 'parsing');
   return searchTree(tree, absPosition);
 }
 
+// TODO: This function appears to be unused.
 function getNextContext(absPosition) {
   var tree = buildQueryTree(editor.getValue(), 0);
   var current = searchTree(tree, absPosition);
   for (var i = absPosition; i < editor.getValue().length + 1; i++) {
     var found = searchTree(tree, i);
     if (current != found && found != undefined) {
-      console.log('Found ' + found.w3name);
+      // console.log('Found ' + found.w3name);
       return found;
     }
   }
   return false;
 }
 
+// For the given query tree, find the element (each element is a "context" from
+// sparql.js:CONTEXTS) that contains the given position and return it.
 function searchTree(tree, absPosition) {
+  // Iterate over all elements in the tree and return the first one that
+  // contains the given `absPosition`. If that position is contained within the
+  // children of an element, recurse (so that, effectively, we only return
+  // leaf elements).
   for (var element of tree) {
     if (absPosition >= element.start && absPosition <= element.end) {
       if (element.children && absPosition >= element.children[0].start && absPosition <= element.children[element.children.length - 1].end) {
@@ -1304,20 +1374,20 @@ function searchTree(tree, absPosition) {
       }
     }
   }
+  log("Could not find context for position " + absPosition, 'parsing');
   return undefined;
 }
 
-/**
- 
-Returns the context by its name
- 
-@params absPosition - absolute position in text
- 
-**/
+// Find the *first* occurrence of the given context (for example, `WhereClause`,
+// see `CONTEXTS` in sparql.js) in the content of the editor window.
+//
+// TODO: Why is it OK to always only find the first match? This is used a lot in
+// sparql.js:`COMPLEXTYPES` and seems to be central for the query parsing.
 function getContextByName(name) {
   var editorContent = editor.getValue()
   var foundContext = undefined;
 
+  // TODO: Should not `CONTEXTS` be an associative array if we use it like this?
   $(CONTEXTS).each(function (index, context) {
 
     if (context.w3name == name) {
@@ -1363,13 +1433,13 @@ function getPrefixLines() {
 }
 
 /**
- 
+
 Returns the value of the given context
- 
+
 @params context - the current context
- 
+
 - Excludes duplicate definitions if told to do so
- 
+
 **/
 function getValueOfContext(context) {
   var editorContent = editor.getValue();
@@ -1384,17 +1454,17 @@ function getValueOfContext(context) {
 }
 
 /**
- 
+
 Returns prefixes to suggest
- 
+
 @params context - the current context
 @params excludeAggregationVariables - excludes variables that are the result of an aggregation (SUM(?x) as ?aggregate_variable)
 @params variableType - can be "text" for text variables, "normal" for normal variables or "both" for both
 @params predicateResultType - only return variables of given type or higher
- 
+
 - Excludes duplicate definitions if told to do so
 - Add list with all unused variables as one suggestion
- 
+
 **/
 function getVariables(context, excludeAggregationVariables, variableType, predicateResultType) {
   var variables = [];
@@ -1454,13 +1524,13 @@ function getVariables(context, excludeAggregationVariables, variableType, predic
 }
 
 /**
- 
+
 Returns prefixes to suggest
- 
+
 @params context - the prefix context
- 
-- Excludes duplicate definitions 
- 
+
+- Excludes duplicate definitions
+
 **/
 function getPrefixSuggestions(context) {
   var prefixes = []
diff --git a/backend/static/js/codemirror/modes/sparql/sparql.js b/backend/static/js/codemirror/modes/sparql/sparql.js
index 7e866bfb..778558fc 100644
--- a/backend/static/js/codemirror/modes/sparql/sparql.js
+++ b/backend/static/js/codemirror/modes/sparql/sparql.js
@@ -41,7 +41,7 @@ const CONTEXTS = [
   },
   {
     w3name: 'Filter',
-    definition: /Filter \(([\s\S]*)\)/gi,
+    definition: /FILTER \(([\s\S]*)\)/gi,
   },
   {
     w3name: 'ValuesClause',
@@ -69,6 +69,8 @@ const CONTEXTS = [
   },
 ];
 
+// TODO: Understand how the unnamed function in `suggestions`is called and with
+// which `c`.
 const COMPLEXTYPES = [
   {
     name: 'PREFIX',
diff --git a/backend/static/js/helper.js b/backend/static/js/helper.js
index f5a34fc2..b402aba0 100644
--- a/backend/static/js/helper.js
+++ b/backend/static/js/helper.js
@@ -444,19 +444,22 @@ async function rewriteQuery(query, kwargs = {}) {
 function rewriteQueryNoAsyncPart(query) {
   var query_rewritten = query;
 
-  // HACK 1: Rewrite FILTER CONTAINS(?title, "info* retr*") using
+  // HACK 1: Rewrite FILTER KEYWORDS(?title, "info* retr*") using
   // ql:contains-entity and ql:contains-word.
-  var num_rewrites_filter_contains = 0;
-  var m_var = "?qlm_";
-  var filter_contains_re = /FILTER\s+CONTAINS\((\?[\w_]+),\s*(\"[^\"]+\")\)\s*\.?\s*/i;
-  while (query_rewritten.match(filter_contains_re)) {
-    query_rewritten = query_rewritten.replace(filter_contains_re,
-         m_var + ' ql:contains-entity $1 . ' + m_var + ' ql:contains-word $2 . ');
-    m_var = m_var + "i";
-    num_rewrites_filter_contains += 1;
-  }
-  if (num_rewrites_filter_contains > 0) {
-    console.log("Rewrote query with \"FILTER CONTAINS\"");
+  const rewriteFilterKeywords = true;
+  if (rewriteFilterKeywords) {
+    var num_rewrites_filter_contains = 0;
+    var m_var = "?qlm_";
+    var filter_contains_re = /FILTER\s+KEYWORDS\((\?[\w_]+),\s*(\"[^\"]+\")\)\s*\.?\s*/i;
+    while (query_rewritten.match(filter_contains_re)) {
+      query_rewritten = query_rewritten.replace(filter_contains_re,
+           m_var + ' ql:contains-entity $1 . ' + m_var + ' ql:contains-word $2 . ');
+      m_var = m_var + "i";
+      num_rewrites_filter_contains += 1;
+    }
+    if (num_rewrites_filter_contains > 0) {
+      console.log("Rewrote query with \"FILTER KEYWORDS\"");
+    }
   }
 
   // HACK 2: Rewrite query to use ql:has-predicate if it fits a certain pattern
@@ -854,6 +857,38 @@ function htmlEscape(str) {
 // table.
 function getFormattedResultEntry(str, maxLength, column = undefined) {
 
+  // Get the variable name from the table header. TODO: it is inefficient to do
+  // this for every table entry.
+  var var_name = $($("#resTable").find("th")[column + 1]).html();
+
+  // If the entry is or contains a link, make it clickable (see where these
+  // variables are set in the following code).
+  let isLink = false;
+  let linkStart = "";
+  let linkEnd = "";
+
+  // HACK: If the variable ends in "_sparql" or "_mapview", consider the value
+  // as a SPARQL query, and show it in the QLever UI or on a map, respectively.
+  if (var_name.endsWith("_sparql") || var_name.endsWith("_mapview")) {
+    isLink = true;
+    if (var_name.endsWith("_sparql")) {
+      mapview_url = `https://qlever.cs.uni-freiburg.de/${SLUG}/` +
+                    `?query=${encodeURIComponent(str)}`;
+      icon_class = "glyphicon glyphicon-search";
+      str = "Query view";
+    } else {
+      mapview_url = `https://qlever.cs.uni-freiburg.de/mapui-petri/` +
+                    `?query=${encodeURIComponent(str)}` +
+                    `&mode=objects&backend=${BASEURL}`;
+      icon_class = "glyphicon glyphicon-globe";
+      str = "Map view";
+    }
+    linkStart = `<span style="white-space: nowrap;">` +
+                `<i class="${icon_class}"></i> ` +
+                `<a href="${mapview_url}" target="_blank">`;
+    linkEnd = '</a></span>';
+  }
+
   // TODO: Do we really want to replace each _ by a space right in the
   // beginning?
   str = str.replace(/_/g, ' ');
@@ -913,7 +948,6 @@ function getFormattedResultEntry(str, maxLength, column = undefined) {
 
   // HACK Hannah 16.09.2021: Custom formatting depending on the variable name in
   // the column header.
-  var var_name = $($("#resTable").find("th")[column + 1]).html();
   // console.log("Check if \"" + str + "\" in column \"" + var_name + "\" is a float ...");
   if (var_name.endsWith("?note") || var_name.endsWith("_note")) str = parseFloat(str).toFixed(2).toString();
   if (var_name.endsWith("_per_paper")) str = parseFloat(str).toFixed(2).toString();
@@ -924,9 +958,6 @@ function getFormattedResultEntry(str, maxLength, column = undefined) {
 
   pos = cpy.lastIndexOf("^^")
   pos_http = cpy.indexOf("http");
-  let isLink = false;
-  let linkStart = "";
-  let linkEnd = "";
 
   // For typed literals (with a ^^ part), prepend icon to header that links to
   // that type.
@@ -956,7 +987,7 @@ function getFormattedResultEntry(str, maxLength, column = undefined) {
 
   // For IRIs that start with http display the item depending on the link type.
   // For images, a thumbnail of the image is shown. For other links, prepend a
-  // symbol that depends on the link tpye and links to the respective URL.
+  // symbol that depends on the link type and links to the respective URL.
   //
   // TODO: What if http occur somewhere inside a literal or a link?
   } else if (pos_http > 0) {
diff --git a/backend/static/js/qleverUI.js b/backend/static/js/qleverUI.js
index 737f866f..fab512fe 100755
--- a/backend/static/js/qleverUI.js
+++ b/backend/static/js/qleverUI.js
@@ -33,7 +33,7 @@ $(window).resize(function (e) {
 });
 
 $(document).ready(function () {
-  
+
   // Initialize the editor.
   editor = CodeMirror.fromTextArea(document.getElementById("query"), {
     mode: "application/sparql-query", indentWithTabs: true, smartIndent: false,
@@ -53,10 +53,10 @@ $(document).ready(function () {
       "Ctrl-R": "replace"
     },
   });
-  
+
   // Set the width of the editor window.
   editor.setSize($('#queryBlock').width(), 350);
-  
+
   // Make the editor resizable.
   $('.CodeMirror').resizable({
     resize: function () {
@@ -64,44 +64,44 @@ $(document).ready(function () {
       editor.setSize($(this).width(), $(this).height());
     }
   });
-  
+
   // Initialize the tooltips.
   $('[data-toggle="tooltip"]').tooltip();
-  
+
   // If there is a theme cookie: use it!
   if (getCookie("theme") != "") {
     changeTheme(getCookie("theme"));
   }
-  
+
   // Load the backends statistics.
   handleStatsDisplay();
-  
+
   // Initialize the name hover.
   if (SUBJECTNAME || PREDICATENAME || OBJECTNAME) {
     $('.cm-entity').hover(showRealName);
   }
-  
+
   // Initialization done.
   log('Editor initialized', 'other');
-  
+
   // Do some custom activities on cursor activity
   editor.on("cursorActivity", function (instance) {
     $('[data-tooltip=tooltip]').tooltip('hide');
     cleanLines(instance);
   });
-  
+
   editor.on("update", function (instance, event) {
     $('[data-tooltip=tooltip]').tooltip('hide');
-    
+
     // (re)initialize the name hover
     if (SUBJECTNAME || PREDICATENAME || OBJECTNAME) {
       $('.cm-entity').hover(showRealName);
     }
   });
-  
+
   // Do some custom activities (overwrite codemirror behaviour)
   editor.on("keyup", function (instance, event) {
-    
+
     // For each prefix in COLLECTEDPREFIXES, check whether it occurs somewhere
     // in the query and if so, add it before the first SELECT (and move
     // the cursor accordingly).
@@ -128,7 +128,7 @@ $(document).ready(function () {
     var line = instance.getLine(cur.line);
     var token = instance.getTokenAt(cur);
     var string = '';
-    
+
     // do not overwrite ENTER inside an completion window
     // esc - 27
     // arrow left - 37
@@ -136,7 +136,7 @@ $(document).ready(function () {
     // arrow right - 39
     // arrow down - 40
     if (instance.state.completionActive || event.keyCode == 27 || (event.keyCode >= 37 && event.keyCode <= 40)) {
-      
+
       // for for autocompletions opened unintented
       if (line[cur.ch] == "}" || line[cur.ch + 1] == "}" || line[cur.ch - 1] == "}") {
         if(instance && instance.state && instance.state.completionActive){
@@ -145,12 +145,12 @@ $(document).ready(function () {
       }
       return;
     }
-    
+
     if (token.string.match(new RegExp('^[.`\w?<@]\w*$'))) {
       string = token.string;
     }
     // do not suggest anything inside a word
-    
+
     if ((line[cur.ch] == " " || line[cur.ch + 1] == " " || line[cur.ch + 1] == undefined) && line[cur.ch] != "}" && line[cur.ch + 1] != "}" && line[cur.ch - 1] != "}") {
       // invoke autocompletion after a very short delay
       window.setTimeout(function () {
@@ -162,17 +162,17 @@ $(document).ready(function () {
       console.warn('Skipped completion due to cursor position');
     }
   });
-  
+
   // when completion is chosen - remove the counter badge
   editor.on("endCompletion", function () { $('#aBadge').remove(); });
-  
+
   function showRealName(element) {
-    
+
     // collect prefixes (as string and dict)
     // TODO: move this to a function. Also use this new function in sparql-hint.js
     var prefixes = "";
     var lines = getPrefixLines();
-    
+
     for (var line of lines) {
       if (line.trim().startsWith("PREFIX")) {
         var match = /PREFIX (.*): ?<(.*)>/g.exec(line.trim());
@@ -181,22 +181,22 @@ $(document).ready(function () {
         }
       }
     }
-    
+
     // TODO: move this "get current element with its prefix" to a function. Also use this new function in sparql-hint.js
     values = $(this).parent().text().trim().split(' ');
     element = $(this).text().trim();
     domElement = this;
-    
+
     if ($(this).prev().hasClass('cm-prefix-name') || $(this).prev().hasClass('cm-string-language')) {
       element = $(this).prev().text() + element;
     }
-    
+
     if ($(this).next().hasClass('cm-entity-name')) {
       element = element + $(this).next().text();
     }
-    
+
     index = values.indexOf(element.replace(/^\^/, ""));
-    
+
     if (index == 0) {
       if (SUBJECTNAME != "") {
         addNameHover(element, domElement, subjectNames, SUBJECTNAME, prefixes);
@@ -210,7 +210,7 @@ $(document).ready(function () {
         addNameHover(element, domElement, objectNames, OBJECTNAME, prefixes);
       }
     }
-    
+
     return true;
   }
 
@@ -258,7 +258,7 @@ $(document).ready(function () {
     // });
     // window.location.href = await getQueryString(query) + "&action=csv_export";
   });
-  
+
   // TSV report: like for CSV report above.
   $("#tsvbtn").click(async function () {
     log('Download TSV', 'other');
@@ -270,7 +270,7 @@ $(document).ready(function () {
     download_link.click();
     // window.location.href = await getQueryString(query) + "&action=tsv_export";
   });
-  
+
   // Generating the various links for sharing.
   $("#sharebtn").click(async function () {
     // Rewrite the query, normalize it, and escape quotes.
@@ -309,10 +309,10 @@ $(document).ready(function () {
         + " --data \"" + queryRewrittenAndNormalizedAndWithEscapedQuotes + "\"");
       $("#queryStringUnescaped").val(queryRewrittenAndNormalizedAndWithEscapedQuotes);
     }, "json");
-    
+
     if (editor.state.completionActive) { editor.state.completionActive.close(); }
   });
-  
+
   $(".copy-clipboard-button").click(function () {
     var link = $(this).parent().parent().find("input")[0];
     link.select();
@@ -320,12 +320,12 @@ $(document).ready(function () {
     document.execCommand("copy");
     $(this).parent().parent().parent().find(".ok-text").collapse("show");
   });
-  
+
 });
 
 function addNameHover(element, domElement, list, namepredicate, prefixes) {
   element = element.replace(/^(@[a-zA-Z-]+@|\^)/, "");
-  
+
   if ($(domElement).data('tooltip') == 'tooltip') {
     return;
   }
@@ -365,7 +365,7 @@ function getResultTime(resultTimes) {
     parseFloat(resultTimes.computeResult.replace(/[^\d\.]/g, ""))
   ];
   timeList.push(timeList[0] - timeList[1]);  // time for resolving and sending
-  
+
   for (const i in timeList) {
     const time = timeList[i];
     let timeAmount = Math.round(time);
@@ -444,7 +444,7 @@ async function processQuery(sendLimit=0, element=$("#exebtn")) {
   log('Preparing query...', 'other');
   log('Element: ' + element, 'other');
   if (sendLimit >= 0) { displayStatus("Waiting for response..."); }
-  
+
   $(element).find('.glyphicon').addClass('glyphicon-spin glyphicon-refresh');
   $(element).find('.glyphicon').removeClass('glyphicon-remove');
   $(element).find('.glyphicon').css('color', $(element).css('color'));
@@ -489,7 +489,7 @@ async function processQuery(sendLimit=0, element=$("#exebtn")) {
     headers: headers,
     success: function (result) {
       log('Evaluating and displaying results...', 'other');
-      
+
       $(element).find('.glyphicon').removeClass('glyphicon-spin');
 
       // For non-query commands like "cmd=clear-cache" just remove the "Waiting
@@ -524,7 +524,7 @@ async function processQuery(sendLimit=0, element=$("#exebtn")) {
       const columns = result.selected;
 
       // If more than predefined number of results, create "Show all" button
-      // (onclick action defined further down). 
+      // (onclick action defined further down).
       let showAllButton = "";
       if (nofRows < parseInt(resultSize)) {
         showAllButton = "<a id=\"show-all\" class=\"btn btn-default\">"
@@ -555,7 +555,7 @@ async function processQuery(sendLimit=0, element=$("#exebtn")) {
       // the Django configuration of the respective backend).
       var res = "<div id=\"res\">";
       if (showAllButton || (mapViewButtonVanilla && mapViewButtonPetri)) {
-        if (BASEURL.match("wikidata|osm-")) {
+        if (BASEURL.match("wikidata|osm-|dblp")) {
           res += `<div class="pull-right" style="margin-left: 1em;">${showAllButton} ${mapViewButtonPetri}</div>`;
           // res += `<div class="pull-right" style="margin-left: 1em;">${showAllButton} ${mapViewButtonVanilla} ${mapViewButtonPetri}</div>`;
         } else {
@@ -641,7 +641,7 @@ async function processQuery(sendLimit=0, element=$("#exebtn")) {
       $("html, body").animate({
         scrollTop: $("#resTable").scrollTop() + 500
       }, 500);
-      
+
       // MAX_VALUE ensures this always has priority over the websocket updates
       appendRuntimeInformation(result.runtimeInformation, result.query, result.time, { queryId, updateTimeStamp: Number.MAX_VALUE });
       renderRuntimeInformationToDom();
@@ -674,12 +674,12 @@ async function processQuery(sendLimit=0, element=$("#exebtn")) {
     }
   });
 }
-  
+
 function handleStatsDisplay() {
   log('Loading backend statistics...', 'other');
   $('#statsButton span').html('Loading information...');
   $('#statsButton').attr('disabled', 'disabled');
-  
+
   $.getJSON(BASEURL + "?cmd=stats", function (result) {
     log('Evaluating and displaying stats...', 'other');
     $("#kbname").html(result.kbindex ?? result["name-index"]);
@@ -730,7 +730,7 @@ function renderRuntimeInformationToDom(entry = undefined) {
     runtime_info,
     query
   } = entry || Array.from(request_log.values()).pop();
-  
+
   if (runtime_info["query_execution_tree"] === null) {
     $("#result-query").text("");
     $("#meta-info").text("");
@@ -801,7 +801,7 @@ function renderRuntimeInformationToDom(entry = undefined) {
   $("p.node-status").filter(function() { return $(this).text() === "failed because child failed"}).addClass("child-failed");
   $("p.node-status").filter(function() { return $(this).text() === "not yet started"}).parent().addClass("not-started");
   $("p.node-status").filter(function() { return $(this).text() === "optimized out"}).addClass("optimized-out");
-  
+
   if ($('#logRequests').is(':checked')) {
     const queryHistoryList = $("<ul/>", { class: "pagination" });
     // Note: when we later iterate over this `Map`, we get the key-value