Correct CSP source values (mdn#35947)

* Correct headers syntax descriptions

* Correct headers syntax descriptions, the rest

* Update some links

* Update form-action

* Reformat fetch directive syntax

* Give a clue about what source expressions are like

* Mention 'none' in source values page

* clarify

files/en-us/mozilla/add-ons/webextensions/manifest.json/content_security_policy/index.md

@@ -65,7 +65,7 @@ In Manifest V2, a source for a script directive is considered secure if it meets
 - Remote sources must not use wildcards for any domains in the [public suffix list](https://publicsuffix.org/list/) (so `*.co.uk` and `*.blogspot.com` are not allowed, although `*.foo.blogspot.com` is permitted).
 - All sources must specify a host.
 - The only permitted schemes for sources are `blob:`, `filesystem:`, `moz-extension:`, `https:`, and `wss:`.
-- The only permitted [keywords](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/default-src#sources) are: `'none'`, `'self'`, `'unsafe-eval'`, and `'wasm-unsafe-eval'`.
+- The only permitted [keywords](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources#sources) are: `'none'`, `'self'`, `'unsafe-eval'`, and `'wasm-unsafe-eval'`.
 
 ## object-src directive
 

files/en-us/web/http/headers/content-security-policy/base-uri/index.md

@@ -28,16 +28,24 @@ The HTTP {{HTTPHeader("Content-Security-Policy")}} **`base-uri`** directive rest
 
 ## Syntax
 
-One or more _sources_ can be allowed for the base-uri policy:
-
 ```http
-Content-Security-Policy: base-uri <source>;
-Content-Security-Policy: base-uri <source> <source>;
+Content-Security-Policy: base-uri 'none';
+Content-Security-Policy: base-uri <source-expression-list>;
 ```
 
-### Sources
+This directive may have one of the following values:
+
+- `'none'`
+  - : No base URI may be set using a `<base>` element. The single quotes are mandatory.
+- `<source-expression-list>`
+
+  - : A space-separated list of _source expression_ values. A `<base>` element may set a base URI if its value matches any of the given source expressions.
+
+    Source expressions are specified as keyword values or URL patterns: the syntax for each source expression is given in [CSP Source Values](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources). However, only the following subset of those values apply to `base-uri`:
 
-This directive uses the same [CSP Source Values](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources#sources) syntax for arguments as other CSP directives. However, only values that match URLs make sense for `base-uri`, including `<host-source>`, `<scheme-source>`, `'self'`, and `'none'`.
+    - `<host-source>`
+    - `<scheme-source>`
+    - the keyword value `'self'`.
 
 ## Examples
 

files/en-us/web/http/headers/content-security-policy/child-src/index.md

@@ -35,18 +35,20 @@ network errors by the user agent.
 
 ## Syntax
 
-One or more sources can be allowed for the `child-src` policy:
-
 ```http
-Content-Security-Policy: child-src <source>;
-Content-Security-Policy: child-src <source> <source>;
+Content-Security-Policy: child-src 'none';
+Content-Security-Policy: child-src <source-expression-list>;
 ```
 
-### Sources
+This directive may have one of the following values:
+
+- `'none'`
+  - : No resources of this type may be loaded. The single quotes are mandatory.
+- `<source-expression-list>`
 
-`<source>` can be any one of the values listed in [CSP Source Values](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources#sources).
+  - : A space-separated list of _source expression_ values. Resources of this type may be loaded if they match any of the given source expressions.
 
-Note that this same set of values can be used in all {{Glossary("fetch directive", "fetch directives")}} (and a [number of other directives](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources#relevant_directives)).
+    Source expressions are specified as keyword values or URL patterns: the syntax for each source expression is given in [CSP Source Values](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources).
 
 ## Examples
 

files/en-us/web/http/headers/content-security-policy/connect-src/index.md

@@ -9,14 +9,14 @@ browser-compat: http.headers.Content-Security-Policy.connect-src
 
 The HTTP {{HTTPHeader("Content-Security-Policy")}} (CSP)
 **`connect-src`** directive restricts the URLs which can be
-loaded using script interfaces. The APIs that are restricted are:
+loaded using script interfaces. The following APIs are controlled by this directive:
 
-- {{HTMLElement("a")}} [`ping`](/en-US/docs/Web/HTML/Element/a#ping),
-- {{domxref("Window/fetch", "fetch()")}},
-- {{domxref("XMLHttpRequest")}},
-- {{domxref("WebSocket")}},
-- {{domxref("EventSource")}}, and
-- {{domxref("Navigator.sendBeacon()")}}.
+- The [`ping`](/en-US/docs/Web/HTML/Element/a#ping) attribute in {{htmlelement("a")}} elements
+- {{domxref("Window/fetch", "fetch()")}}
+- {{domxref("XMLHttpRequest")}}
+- {{domxref("WebSocket")}}
+- {{domxref("EventSource")}}
+- {{domxref("Navigator.sendBeacon()")}}
 
 > **Note:** `connect-src 'self'` does not resolve to websocket
 > schemes in all browsers, more info in this [issue](https://github.com/w3c/webappsec-csp/issues/7).
@@ -43,18 +43,20 @@ loaded using script interfaces. The APIs that are restricted are:
 
 ## Syntax
 
-One or more sources can be allowed for the connect-src policy:
-
 ```http
-Content-Security-Policy: connect-src <source>;
-Content-Security-Policy: connect-src <source> <source>;
+Content-Security-Policy: connect-src 'none';
+Content-Security-Policy: connect-src <source-expression-list>;
 ```
 
-### Sources
+This directive may have one of the following values:
+
+- `'none'`
+  - : No resources of this type may be loaded. The single quotes are mandatory.
+- `<source-expression-list>`
 
-`<source>` can be any one of the values listed in [CSP Source Values](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources#sources).
+  - : A space-separated list of _source expression_ values. Resources of this type may be loaded if they match any of the given source expressions.
 
-Note that this same set of values can be used in all {{Glossary("fetch directive", "fetch directives")}} (and a [number of other directives](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources#relevant_directives)).
+    Source expressions are specified as keyword values or URL patterns: the syntax for each source expression is given in [CSP Source Values](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources).
 
 ## Examples
 

files/en-us/web/http/headers/content-security-policy/default-src/index.md

@@ -41,18 +41,20 @@ The HTTP {{HTTPHeader("Content-Security-Policy")}} (CSP) **`default-src`** direc
 
 ## Syntax
 
-One or more sources can be allowed for the `default-src` policy:
-
 ```http
-Content-Security-Policy: default-src <source>;
-Content-Security-Policy: default-src <source> <source>;
+Content-Security-Policy: default-src 'none';
+Content-Security-Policy: default-src <source-expression-list>;
 ```
 
-### Sources
+This directive may have one of the following values:
+
+- `'none'`
+  - : No resources may be loaded. The single quotes are mandatory.
+- `<source-expression-list>`
 
-`<source>` can be any one of the values listed in [CSP Source Values](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources#sources).
+  - : A space-separated list of _source expression_ values. Resources may be loaded if they match any of the given source expressions.
 
-Note that this same set of values can be used in all {{Glossary("fetch directive", "fetch directives")}} (and a [number of other directives](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources#relevant_directives)).
+    Source expressions are specified as keyword values or URL patterns: the syntax for each source expression is given in [CSP Source Values](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources).
 
 ## Examples
 

files/en-us/web/http/headers/content-security-policy/font-src/index.md

@@ -33,18 +33,20 @@ valid sources for fonts loaded using {{cssxref("@font-face")}}.
 
 ## Syntax
 
-One or more sources can be allowed for the `font-src` policy:
-
 ```http
-Content-Security-Policy: font-src <source>;
-Content-Security-Policy: font-src <source> <source>;
+Content-Security-Policy: font-src 'none';
+Content-Security-Policy: font-src <source-expression-list>;
 ```
 
-### Sources
+This directive may have one of the following values:
+
+- `'none'`
+  - : No resources of this type may be loaded. The single quotes are mandatory.
+- `<source-expression-list>`
 
-`<source>` can be any one of the values listed in [CSP Source Values](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources#sources).
+  - : A space-separated list of _source expression_ values. Resources of this type may be loaded if they match any of the given source expressions.
 
-Note that this same set of values can be used in all {{Glossary("fetch directive", "fetch directives")}} (and a [number of other directives](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources#relevant_directives)).
+    Source expressions are specified as keyword values or URL patterns: the syntax for each source expression is given in [CSP Source Values](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources).
 
 ## Examples
 

files/en-us/web/http/headers/content-security-policy/form-action/index.md

@@ -31,18 +31,24 @@ The HTTP {{HTTPHeader("Content-Security-Policy")}} (CSP) **`form-action`** direc
 
 ## Syntax
 
-One or more sources can be set for the `form-action` policy:
-
 ```http
-Content-Security-Policy: form-action <source>;
-Content-Security-Policy: form-action <source> <source>;
+Content-Security-Policy: form-action 'none';
+Content-Security-Policy: form-action <source-expression-list>;
 ```
 
-### Sources
+This directive may have one of the following values:
+
+- `'none'`
+  - : No form submissions may be made. The single quotes are mandatory.
+- `<source-expression-list>`
+
+  - : A space-separated list of _source expression_ values. Form submissions may be made to URLs that match any of the given source expressions.
 
-`<source>` can be any one of the values listed in [CSP Source Values](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources#sources).
+    Source expressions are specified as keyword values or URL patterns: the syntax for each source expression is given in [CSP Source Values](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources). However, only the following subset of those values apply to `form-action`:
 
-Note that this same set of values can be used in all {{Glossary("fetch directive", "fetch directives")}} (and a [number of other directives](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources#relevant_directives)).
+    - `<host-source>`
+    - `<scheme-source>`
+    - the keyword value `'self'`.
 
 ## Examples
 

files/en-us/web/http/headers/content-security-policy/frame-src/index.md

@@ -38,18 +38,20 @@ browsing contexts loading using elements such as {{HTMLElement("frame")}} and
 
 ## Syntax
 
-One or more sources can be allowed for the `frame-src` policy:
-
 ```http
-Content-Security-Policy: frame-src <source>;
-Content-Security-Policy: frame-src <source> <source>;
+Content-Security-Policy: frame-src 'none';
+Content-Security-Policy: frame-src <source-expression-list>;
 ```
 
-### Sources
+This directive may have one of the following values:
+
+- `'none'`
+  - : No resources of this type may be loaded. The single quotes are mandatory.
+- `<source-expression-list>`
 
-`<source>` can be any one of the values listed in [CSP Source Values](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources#sources).
+  - : A space-separated list of _source expression_ values. Resources of this type may be loaded if they match any of the given source expressions.
 
-Note that this same set of values can be used in all {{Glossary("fetch directive", "fetch directives")}} (and a [number of other directives](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources#relevant_directives)).
+    Source expressions are specified as keyword values or URL patterns: the syntax for each source expression is given in [CSP Source Values](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources).
 
 ## Examples
 

files/en-us/web/http/headers/content-security-policy/img-src/index.md

@@ -31,18 +31,20 @@ The HTTP {{HTTPHeader("Content-Security-Policy")}} **`img-src`** directive speci
 
 ## Syntax
 
-One or more sources can be allowed for the `img-src` policy:
-
 ```http
-Content-Security-Policy: img-src <source>;
-Content-Security-Policy: img-src <source> <source>;
+Content-Security-Policy: img-src 'none';
+Content-Security-Policy: img-src <source-expression-list>;
 ```
 
-### Sources
+This directive may have one of the following values:
+
+- `'none'`
+  - : No resources of this type may be loaded. The single quotes are mandatory.
+- `<source-expression-list>`
 
-`<source>` can be any one of the values listed in [CSP Source Values](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources#sources).
+  - : A space-separated list of _source expression_ values. Resources of this type may be loaded if they match any of the given source expressions.
 
-Note that this same set of values can be used in all {{Glossary("fetch directive", "fetch directives")}} (and a [number of other directives](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources#relevant_directives)).
+    Source expressions are specified as keyword values or URL patterns: the syntax for each source expression is given in [CSP Source Values](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources).
 
 ## Examples
 

files/en-us/web/http/headers/content-security-policy/index.md

@@ -170,7 +170,7 @@ Reporting directives control the destination URL for CSP violation reports in `C
 ## Values
 
 An overview of the allowed values are listed below.
-For detailed reference see [CSP Source Values](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources#sources) and the documentation for individual directives.
+For detailed reference see [CSP Source Values](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources) and the documentation for individual directives.
 
 ### Keyword values
 

files/en-us/web/http/headers/content-security-policy/manifest-src/index.md

@@ -34,18 +34,20 @@ to the resource.
 
 ## Syntax
 
-One or more sources can be allowed for the `manifest-src` policy:
-
 ```http
-Content-Security-Policy: manifest-src <source>;
-Content-Security-Policy: manifest-src <source> <source>;
+Content-Security-Policy: manifest-src 'none';
+Content-Security-Policy: manifest-src <source-expression-list>;
 ```
 
-### Sources
+This directive may have one of the following values:
+
+- `'none'`
+  - : No resources of this type may be loaded. The single quotes are mandatory.
+- `<source-expression-list>`
 
-`<source>` can be any one of the values listed in [CSP Source Values](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources#sources).
+  - : A space-separated list of _source expression_ values. Resources of this type may be loaded if they match any of the given source expressions.
 
-Note that this same set of values can be used in all {{Glossary("fetch directive", "fetch directives")}} (and a [number of other directives](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources#relevant_directives)).
+    Source expressions are specified as keyword values or URL patterns: the syntax for each source expression is given in [CSP Source Values](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources).
 
 ## Examples
 

files/en-us/web/http/headers/content-security-policy/media-src/index.md

@@ -33,18 +33,20 @@ media using the {{HTMLElement("audio")}} and {{HTMLElement("video")}} elements.
 
 ## Syntax
 
-One or more sources can be allowed for the `media-src` policy:
-
 ```http
-Content-Security-Policy: media-src <source>;
-Content-Security-Policy: media-src <source> <source>;
+Content-Security-Policy: media-src 'none';
+Content-Security-Policy: media-src <source-expression-list>;
 ```
 
-### Sources
+This directive may have one of the following values:
+
+- `'none'`
+  - : No resources of this type may be loaded. The single quotes are mandatory.
+- `<source-expression-list>`
 
-`<source>` can be any one of the values listed in [CSP Source Values](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources#sources).
+  - : A space-separated list of _source expression_ values. Resources of this type may be loaded if they match any of the given source expressions.
 
-Note that this same set of values can be used in all {{Glossary("fetch directive", "fetch directives")}} (and a [number of other directives](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources#relevant_directives)).
+    Source expressions are specified as keyword values or URL patterns: the syntax for each source expression is given in [CSP Source Values](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources).
 
 ## Examples
 

files/en-us/web/http/headers/content-security-policy/object-src/index.md

@@ -40,18 +40,20 @@ The HTTP {{HTTPHeader("Content-Security-Policy")}}
 
 ## Syntax
 
-One or more sources can be allowed for the `object-src` policy:
-
 ```http
-Content-Security-Policy: object-src <source>;
-Content-Security-Policy: object-src <source> <source>;
+Content-Security-Policy: object-src 'none';
+Content-Security-Policy: object-src <source-expression-list>;
 ```
 
-### Sources
+This directive may have one of the following values:
+
+- `'none'`
+  - : No resources of this type may be loaded. The single quotes are mandatory.
+- `<source-expression-list>`
 
-`<source>` can be any one of the values listed in [CSP Source Values](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources#sources).
+  - : A space-separated list of _source expression_ values. Resources of this type may be loaded if they match any of the given source expressions.
 
-Note that this same set of values can be used in all {{Glossary("fetch directive", "fetch directives")}} (and a [number of other directives](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources#relevant_directives)).
+    Source expressions are specified as keyword values or URL patterns: the syntax for each source expression is given in [CSP Source Values](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources).
 
 ## Examples
 

files/en-us/web/http/headers/content-security-policy/prefetch-src/index.md

@@ -36,18 +36,20 @@ be prefetched or prerendered.
 
 ## Syntax
 
-One or more sources can be allowed for the `prefetch-src` policy:
-
 ```http
-Content-Security-Policy: prefetch-src <source>;
-Content-Security-Policy: prefetch-src <source> <source>;
+Content-Security-Policy: prefetch-src 'none';
+Content-Security-Policy: prefetch-src <source-expression-list>;
 ```
 
-### Sources
+This directive may have one of the following values:
+
+- `'none'`
+  - : No resources of this type may be loaded. The single quotes are mandatory.
+- `<source-expression-list>`
 
-`<source>` can be any one of the values listed in [CSP Source Values](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources#sources).
+  - : A space-separated list of _source expression_ values. Resources of this type may be loaded if they match any of the given source expressions.
 
-Note that this same set of values can be used in all {{Glossary("fetch directive", "fetch directives")}} (and a [number of other directives](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources#relevant_directives)).
+    Source expressions are specified as keyword values or URL patterns: the syntax for each source expression is given in [CSP Source Values](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources).
 
 ## Example