docs: config: obsolete state/index sections and document core.site_ca…

…che_dir (#4448)

* docs: config: add core.site_cache_dir

* docs: config: obsolete state and index sections

content/docs/user-guide/project-structure/configuration.md

@@ -111,6 +111,10 @@ within:
   <abbr>DVC files</abbr> created or modified by DVC commands. The files will not
   be committed. Accepts values `true` and `false` (default).
 
+- `core.site_cache_dir` - specify a custom location for misc temporary files.
+  Read more
+  [here](/doc/user-guide/project-structure/internal-files#site-cache-dir).
+
 </details>
 
 <details>
@@ -360,6 +364,13 @@ Composition].
 
 ## state
 
+<admon type="warn">
+
+This section is obsolete since DVC 2.48.0. Modifying these config options will
+have no effect.
+
+</admon>
+
 - `state.row_limit` - maximum number of entries in state databases. This affects
   the physical size of the state files, as well as the performance of certain
   DVC operations. The default is 10,000,000 rows. The bigger the limit, the
@@ -380,6 +391,13 @@ Composition].
 
 ## index
 
+<admon type="warn">
+
+This section is obsolete since DVC 2.48.0. Modifying these config options will
+have no effect.
+
+</admon>
+
 - `index.dir` - specify a custom location for the directory where remote index
   files will be stored, by default in `.dvc/tmp/index`. This may be necessary
   when using DVC on NFS or other mounted volumes.

content/docs/user-guide/project-structure/internal-files.md

@@ -51,36 +51,6 @@ Not to be confused with `.dvc` files.
 
 - `.dvc/tmp`: Directory for miscellaneous temporary files
 
-- `.dvc/tmp/index`: Directory for remote index files that are used for
-  optimizing `dvc push`, `dvc pull`, `dvc fetch` and `dvc status -c` operations.
-
-  <admon type="info">
-
-  This location may be overridden with `dvc config index.dir`.
-
-  </admon>
-
-- `.dvc/tmp/md5s`: This directory is used for optimization. It contains a SQLite
-  state database that stores hash values for files tracked in a DVC project. It
-  also saves the corresponding timestamps and inodes to avoid unnecessary file
-  hash computations.
-
-  <admon type="info">
-
-  This parent location may be overridden with `dvc config state.dir`.
-
-  </admon>
-
-- `.dvc/tmp/links`: This directory is used to clean up your workspace when
-  calling `dvc checkout`. It contains a SQLite state database that stores a list
-  of file links created by DVC (from cache to <abbr>workspace</abbr>).
-
-  <admon type="info">
-
-  This parent location may be overridden with `dvc config state.dir`.
-
-  </admon>
-
 - `.dvc/tmp/updater`: This file is used to store the latest available version of
   DVC. It's used to remind the user to upgrade when the installed version is
   behind.
@@ -214,3 +184,37 @@ unexpected behavior]).
 
 [avoiding unexpected behavior]:
   /doc/user-guide/project-structure/dvcyaml-files#avoiding-unexpected-behavior
+
+## Site cache dir
+
+Directory used for storing temporary files.
+
+Default location:
+
+| macOS                 | Linux (typical\*) | Windows                        |
+| --------------------- | ----------------- | ------------------------------ |
+| `/Library/Caches/dvc` | `/var/tmp/dvc`    | `C:\ProgramData\iterative\dvc` |
+
+<admon type="info">
+
+This location may be overridden with `dvc config core.site_cache_dir`.
+
+</admon>
+
+<admon type="warn">
+
+Not to be confused with DVC <abbr>cache</abbr>.
+
+</admon>
+
+- `index`: Directory for remote index files that are used for optimizing
+  `dvc push`, `dvc pull`, `dvc fetch` and `dvc status -c` operations.
+
+- `hashes`: This directory is used for optimization. It contains a SQLite state
+  database that stores hash values for files tracked in a DVC project. It also
+  saves the corresponding timestamps and inodes to avoid unnecessary file hash
+  computations.
+
+- `links`: This directory is used to clean up your workspace when calling
+  `dvc checkout`. It contains a SQLite state database that stores a list of file
+  links created by DVC (from cache to <abbr>workspace</abbr>).