chore(http): Refresh headers docs i-r

files/en-us/web/http/headers/if-unmodified-since/index.md

@@ -7,18 +7,14 @@ browser-compat: http.headers.If-Unmodified-Since
 
 {{HTTPSidebar}}
 
-The HyperText Transfer Protocol (HTTP) **`If-Unmodified-Since`** request header makes the
-request for the resource conditional: the server will send the requested resource or accept it in
-the case of a {{HTTPMethod("POST")}} or another non-{{Glossary("Safe/HTTP", "safe")}} method only if the resource has not been modified after the date specified by this HTTP header. If the resource has been modified
-after the specified date, the response will be a {{HTTPStatus("412", "412 Precondition Failed")}} error.
+The HTTP **`If-Unmodified-Since`** {{glossary("request header")}} makes the request for the resource [conditional](/en-US/docs/Web/HTTP/Conditional_requests).
+The server will send the requested resource (or accept it in the case of a {{HTTPMethod("POST")}} or another non-{{Glossary("Safe/HTTP", "safe")}} method) only if the resource on the server has not been modified after the date in the request header.
+If the resource has been modified after the specified date, the response will be a {{HTTPStatus("412", "412 Precondition Failed")}} error.
 
-The **`If-Unmodified-Since`** HTTP header is commonly used in the following situations:
+The `If-Unmodified-Since` header is commonly used in the following situations:
 
-- In conjunction with non-{{Glossary("Safe/HTTP", "safe")}} methods, like {{HTTPMethod("POST")}},
-  this header can be used to implement an [optimistic concurrency control](https://en.wikipedia.org/wiki/Optimistic_concurrency_control), as is done by some wikis: editions are rejected if the
-  stored document has been modified since the original was retrieved.
-- In conjunction with a range request using the {{HTTPHeader("Range")}} header, this header can
-  be used to ensure that the new fragment requested comes from an unmodified document.
+- In conjunction with non-{{Glossary("Safe/HTTP", "safe")}} methods like {{HTTPMethod("POST")}}, this header can be used to implement an [optimistic concurrency control](https://en.wikipedia.org/wiki/Optimistic_concurrency_control), as is done by some wikis: revision are rejected if the stored document has been modified since the original was retrieved, avoiding conflicts.
+- In conjunction with a range request using the {{HTTPHeader("Range")}} header, this header can be used to ensure that the new fragment requested comes from an unmodified document.
 
 <table class="properties">
   <tbody>
@@ -28,7 +24,7 @@ The **`If-Unmodified-Since`** HTTP header is commonly used in the following situ
     </tr>
     <tr>
       <th scope="row">{{Glossary("Forbidden header name")}}</th>
-      <td>no</td>
+      <td>No</td>
     </tr>
   </tbody>
 </table>
@@ -41,21 +37,21 @@ If-Unmodified-Since: <day-name>, <day> <month> <year> <hour>:<minute>:<second> G
 
 ## Directives
 
-- \<day-name>
-  - : A 3-letter description of the day of the week. One of "Mon", "Tue", "Wed", "Thu", "Fri", "Sat", or "Sun" (case-sensitive).
-- \<day>
-  - : A 2-digit day number of the month. Examples: "04", "23".
-- \<month>
-  - : A 3-letter description of the month. One of "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" (case-sensitive).
-- \<year>
-  - : A 4-digit year number. Examples: "1990", "2016".
-- \<hour>
-  - : A 2-digit hour number based on a 24-hour system. Examples: "09", "23".
-- \<minute>
-  - : A 2-digit minute number. Examples: "04", "59".
-- \<second>
-  - : A 2-digit second number. Examples: "04", "59".
-- `GMT`
+- `<day-name>`
+  - : One of "Mon", "Tue", "Wed", "Thu", "Fri", "Sat", or "Sun" (case-sensitive).
+- `<day>`
+  - : 2 digit day number, e.g., "04" or "23".
+- `<month>`
+  - : One of "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" (case-sensitive).
+- `<year>`
+  - : 4 digit year number, e.g. "1990" or "2016".
+- `<hour>`
+  - : 2 digit hour number, e.g. "09" or "23".
+- `<minute>`
+  - : 2 digit minute number, e.g. "04" or "59".
+- `<second>`
+  - : 2 digit second number, e.g. "04" or "59".
+- GMT
   - : Greenwich Mean Time. HTTP dates are always expressed in GMT, never in local time.
 
 ## Examples
@@ -74,9 +70,8 @@ If-Unmodified-Since: Wed, 21 Oct 2015 07:28:00 GMT
 
 ## See also
 
+- [HTTP Conditional Requests](/en-US/docs/Web/HTTP/Conditional_requests) guide
 - {{HTTPHeader("Last-Modified")}}
-- {{HTTPHeader("If-Modified-Since")}}
-- {{HTTPHeader("If-Match")}}
-- {{HTTPHeader("If-None-Match")}}
-- {{HTTPHeader("Range")}}
-- {{HTTPStatus("412", "412 Precondition Failed")}}
+- {{HTTPHeader("If-Range")}}, {{HTTPHeader("Range")}} range request headers
+- {{HTTPHeader("If-Match")}}, {{HTTPHeader("If-Modified-Since")}}, {{HTTPHeader("If-None-Match")}} conditional request headers
+- {{HTTPStatus("304", "304 Not Modified")}}, {{HTTPStatus("412", "412 Precondition Failed")}} response status codes

files/en-us/web/http/headers/last-modified/index.md

@@ -7,12 +7,9 @@ browser-compat: http.headers.Last-Modified
 
 {{HTTPSidebar}}
 
-The **`Last-Modified`** response HTTP header contains a date
-and time when the origin server believes the resource was last modified. It is used
-as a validator to determine if the resource is the same as the previously stored one. Less accurate
-than an {{HTTPHeader("ETag")}} header, it is a fallback mechanism. Conditional requests
-containing {{HTTPHeader("If-Modified-Since")}} or {{HTTPHeader("If-Unmodified-Since")}}
-headers make use of this field.
+The HTTP **`Last-Modified`** response header contains a date and time when the origin server believes the resource was last modified.
+It is used as a validator in [conditional requests](/en-US/docs/Web/HTTP/Conditional_requests) ({{HTTPHeader("If-Modified-Since")}} or {{HTTPHeader("If-Unmodified-Since")}}) to determine if a requested resource is the same as one already stored by the client.
+It is less accurate than an {{HTTPHeader("ETag")}} for determining file contents, but can be used as a fallback mechanism if ETags are unavailable.
 
 `Last-Modified` is also used by [crawlers](/en-US/docs/Glossary/Crawler) to adjust crawl frequency, by browsers in [heuristic caching](/en-US/docs/Web/HTTP/Caching#heuristic_caching), and by content management systems (CMS) to display the time the content was last modified.
 
@@ -24,13 +21,13 @@ headers make use of this field.
     </tr>
     <tr>
       <th scope="row">{{Glossary("Forbidden header name")}}</th>
-      <td>no</td>
+      <td>No</td>
     </tr>
     <tr>
       <th scope="row">
         {{Glossary("CORS-safelisted response header")}}
       </th>
-      <td>yes</td>
+      <td>Yes</td>
     </tr>
   </tbody>
 </table>
@@ -43,22 +40,21 @@ Last-Modified: <day-name>, <day> <month> <year> <hour>:<minute>:<second> GMT
 
 ## Directives
 
-- \<day-name>
+- `<day-name>`
   - : One of "Mon", "Tue", "Wed", "Thu", "Fri", "Sat", or "Sun" (case-sensitive).
-- \<day>
-  - : 2 digit day number, e.g. "04" or "23".
-- \<month>
-  - : One of "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov",
-    "Dec" (case sensitive).
-- \<year>
+- `<day>`
+  - : 2 digit day number, e.g., "04" or "23".
+- `<month>`
+  - : One of "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" (case-sensitive).
+- `<year>`
   - : 4 digit year number, e.g. "1990" or "2016".
-- \<hour>
+- `<hour>`
   - : 2 digit hour number, e.g. "09" or "23".
-- \<minute>
+- `<minute>`
   - : 2 digit minute number, e.g. "04" or "59".
-- \<second>
+- `<second>`
   - : 2 digit second number, e.g. "04" or "59".
-- `GMT`
+- GMT
   - : Greenwich Mean Time. HTTP dates are always expressed in GMT, never in local time.
 
 ## Examples
@@ -77,6 +73,7 @@ Last-Modified: Wed, 21 Oct 2015 07:28:00 GMT
 
 ## See also
 
-- {{HTTPHeader("If-Modified-Since")}}
-- {{HTTPHeader("If-Unmodified-Since")}}
 - {{HTTPHeader("Etag")}}
+- [HTTP Conditional Requests](/en-US/docs/Web/HTTP/Conditional_requests) guide
+- {{HTTPHeader("If-Match")}}, {{HTTPHeader("If-Modified-Since")}}, {{HTTPHeader("If-Unmodified-Since")}}, {{HTTPHeader("If-None-Match")}} conditional request headers
+- {{HTTPStatus("304", "304 Not Modified")}}, {{HTTPStatus("412", "412 Precondition Failed")}} response status codes

files/en-us/web/http/headers/link/index.md

@@ -7,11 +7,36 @@ browser-compat: http.headers.Link
 
 {{HTTPSidebar}}
 
-The HTTP **`Link`** [entity header](/en-US/docs/Glossary/Entity_header) field provides a means for serializing one or more links in HTTP headers. This header has the same semantics as the HTML {{HTMLElement("link")}} element. The benefit of using the `Link` header is that the browser can start preconnecting or preloading resources before the HTML itself is fetched and processed.
+The HTTP **`Link`** [entity header](/en-US/docs/Glossary/Entity_header) field provides a means for serializing one or more links in HTTP headers.
+This allows the server to point a client to another resource containing metadata about the requested resource.
+This header has the same semantics as the HTML {{HTMLElement("link")}} element.
+One benefit of using the `Link` header is that the browser can start preconnecting or preloading resources before the HTML itself is fetched and processed.
 
-In practice, most [`rel` link types](/en-US/docs/Web/HTML/Attributes/rel) don't have an effect when used with the HTTP header. For example, the `icon` relation only works in HTML, and `stylesheet` does not work reliably across browsers (only in Firefox).
+In practice, most [`rel` link types](/en-US/docs/Web/HTML/Attributes/rel) don't have an effect when used with the HTTP header. 
+For example, the `icon` relation only works in HTML, and `stylesheet` does not work reliably across browsers (only in Firefox).
 The only relations that work reliably are [`preconnect`](/en-US/docs/Web/HTML/Attributes/rel/preconnect) and [`preload`](/en-US/docs/Web/HTML/Attributes/rel/preload), which can be combined with {{HTTPStatus(103, "103 Early Hints")}}.
 
+<table class="properties">
+  <tbody>
+    <tr>
+      <th scope="row">Header type</th>
+      <td>
+        {{Glossary("Entity header")}}
+      </td>
+    </tr>
+    <tr>
+      <th scope="row">{{Glossary("Forbidden header name")}}</th>
+      <td>No</td>
+    </tr>
+    <tr>
+      <th scope="row">
+        {{Glossary("CORS-safelisted response header")}}
+      </th>
+      <td>No</td>
+    </tr>
+  </tbody>
+</table>
+
 ## Syntax
 
 ```http
@@ -24,6 +49,7 @@ Link: <uri-reference>; param1=value1; param2="value2"
 ### Parameters
 
 The link header contains parameters, which are separated with `;` and are equivalent to attributes of the {{HTMLElement("link")}} element.
+Values can be both quoted or unquoted based on [field value component rules](https://www.rfc-editor.org/rfc/rfc7230.html#section-3.2.6), so `x=y` is equivalent to `x="y"`.
 
 ## Examples
 
@@ -41,7 +67,7 @@ Link: https://bad.example; rel="preconnect"
 
 ### Encoding URLs
 
-The URI (absolute or relative) must encode char codes greater than 255:
+The URI (absolute or relative) must {{Glossary("Percent-encoding", "percent-encode")}} character codes greater than 255:
 
 ```http example-good
 Link: <https://example.com/%E8%8B%97%E6%9D%A1>; rel="preconnect"
@@ -59,6 +85,16 @@ You can specify multiple links separated by commas, for example:
 Link: <https://one.example.com>; rel="preconnect", <https://two.example.com>; rel="preconnect", <https://three.example.com>; rel="preconnect"
 ```
 
+### Pagination through links
+
+The `Link` header can provide pagination information to a client, which is commonly used to access resources programmatically:
+
+```http
+Link: <https://api.example.com/issues?page=2>; rel="prev", <https://api.example.com/issues?page=4>; rel="next", <https://api.example.com/issues?page=10>; rel="last", <https://api.example.com/issues?page=1>; rel="first"
+```
+
+In this case, `rel="prev"` and `rel="next"` show link relations for previous and next pages, and there are `rel="last"` and `rel="first"` parameters providing first and last pages of search results.
+
 ### Controlling fetch priority
 
 Even when using [`preload`](/en-US/docs/Web/HTML/Attributes/rel/preload) to fetch a resource as early as possible, different types of content will be fetched earlier or later based on the browser's internal prioritization.
@@ -83,6 +119,7 @@ The `fetchpriority` directive should be used sparingly, and only in cases where
 
 ## See also
 
-- {{HTTPStatus(103, "103 Early Hints")}}
+- {{HTTPStatus("103", "103 Early Hints")}}
 - {{HTMLElement("link")}}
+- [Link Relations](https://www.iana.org/assignments/link-relations/link-relations.xhtml) IANA registry
 - [Optimize resource loading with the Fetch Priority API](https://web.dev/articles/fetch-priority?hl=en#browser_priority_and_fetchpriority) for information about how this API affects priorities on Chrome.

files/en-us/web/http/headers/location/index.md

@@ -7,34 +7,22 @@ browser-compat: http.headers.Location
 
 {{HTTPSidebar}}
 
-The **`Location`** response header indicates the URL to
-redirect a page to. It only provides a meaning when served with a
-`3xx` (redirection) or `201` (created) status response.
+The HTTP **`Location`** response header indicates the URL to redirect a page to.
+It only provides a meaning when served with a `3XX` [redirection response](/en-US/docs/Web/HTTP/Status#redirection_messages) or a {{HTTPStatus("201", "201 Created")}} status response.
 
-In cases of redirection, the HTTP method used to make the new request to fetch the page
-pointed to by `Location` depends on the original method and the kind of
-redirection:
+In redirections, the HTTP method used to make the redirected request to fetch the page pointed to by `Location` depends on the original method and the kind of redirection:
 
-- {{HTTPStatus("303")}} (See Other) responses always lead to the use of a
-  {{HTTPMethod("GET")}} method.
-- {{HTTPStatus("307")}} (Temporary Redirect) and
-  {{HTTPStatus("308")}} (Permanent Redirect) don't change the method used in the
-  original request.
-- {{HTTPStatus("301")}} (Moved Permanently) and {{HTTPStatus("302")}} (Found) don't
-  change the method most of the time, though older user-agents may (so you basically
-  don't know).
+- {{HTTPStatus("303", "303 See Other")}} responses always result in a {{HTTPMethod("GET")}} request in the redirection.
+- {{HTTPStatus("307", "307 Temporary Redirect")}} and {{HTTPStatus("308", "308 Permanent Redirect")}} use the same method as the initiating request.
+- {{HTTPStatus("301", "301 Moved Permanently")}} and {{HTTPStatus("302", "302 Found")}} should use the same request method as the initiating request, although this is not guaranteed for older user-agents.
 
-All responses with one of these status codes send a `Location` header.
+All responses with one of the above status codes include a `Location` header.
 
-In cases of resource creation, it indicates the URL to the newly created resource.
+In cases of resource creation, it indicates the URL of the newly-created resource so that a client can make a request for it immediately.
 
 `Location` and {{HTTPHeader("Content-Location")}} are different.
-`Location` indicates the target of a redirection or the URL of a newly
-created resource. {{HTTPHeader("Content-Location")}} indicates the direct URL to
-use to access the resource when [content negotiation](/en-US/docs/Web/HTTP/Content_negotiation) happened,
-without the need of further content negotiation. `Location` is a header
-associated with the response, while {{HTTPHeader("Content-Location")}} is associated
-with the entity returned.
+`Content-Location` indicates the URL to use to directly access the resource in future when [content negotiation](/en-US/docs/Web/HTTP/Content_negotiation) occurred.
+`Location` is associated with the response, while {{HTTPHeader("Content-Location")}} is associated with the representation that was returned.
 
 <table class="properties">
   <tbody>
@@ -44,7 +32,7 @@ with the entity returned.
     </tr>
     <tr>
       <th scope="row">{{Glossary("Forbidden header name")}}</th>
-      <td>no</td>
+      <td>No</td>
     </tr>
   </tbody>
 </table>
@@ -57,8 +45,8 @@ Location: <url>
 
 ## Directives
 
-- \<url>
-  - : A relative (to the request URL) or absolute URL.
+- `<url>`
+  - : May be relative to the request URL or an absolute URL.
 
 ## Examples
 
@@ -77,6 +65,4 @@ Location: /index.html
 ## See also
 
 - {{HTTPHeader("Content-Location")}}
-- Status of responses including a `Location` header: {{HTTPStatus("201")}},
-  {{HTTPStatus("301")}}, {{HTTPStatus("302")}}, {{HTTPStatus("303")}},
-  {{HTTPStatus("307")}}, {{HTTPStatus("308")}}.
+- Status responses including a `Location` header: {{HTTPStatus("201")}}, {{HTTPStatus("301")}}, {{HTTPStatus("302")}}, {{HTTPStatus("303")}}, {{HTTPStatus("307")}}, {{HTTPStatus("308")}}.

files/en-us/web/http/headers/max-forwards/index.md

@@ -7,7 +7,11 @@ spec-urls: https://httpwg.org/specs/rfc9110.html#field.max-forwards
 
 {{HTTPSidebar}}
 
-The **`Max-Forwards`** request HTTP header is used with the [`TRACE`](/en-US/docs/Web/HTTP/Methods/TRACE) method to limit the number of nodes (usually proxies) that request goes through. Its value is an integer value indicating the _maximum amount_ of nodes it must visit. At each node, the value is decremented and the `TRACE` request is forwarded to the next node, until the destination is reached, or the received value of `Max-Forwards` is zero. The request is then sent back, except for some headers, as the body of a `200 OK` response.
+The HTTP **`Max-Forwards`** request header is used with the {{HTTPMethod("TRACE")}} method to limit the number of nodes (usually {{Glossary("Proxy_server", "proxies")}}) that the request goes through.
+Its value is an integer indicating the _maximum amount_ of nodes it must visit.
+At each node, the value is decremented and the `TRACE` request is forwarded to the next node until the destination is reached or the received value of `Max-Forwards` is zero.
+The request is then sent back (excluding sensitive headers where appropriate) as the body of a {{HTTPStatus("200")}} response.
+This allows the client to see what is being received at the other end of the request chain (the {{HTTPHeader("Via")}} header is of particular interest) for testing or diagnostic purposes.
 
 If the `Max-Forwards` header is not present in a `TRACE` request, a node will assume that there is no maximum number of forwards.
 
@@ -19,7 +23,7 @@ If the `Max-Forwards` header is not present in a `TRACE` request, a node will as
     </tr>
     <tr>
       <th scope="row">{{Glossary("Forbidden header name")}}</th>
-      <td>no</td>
+      <td>No</td>
     </tr>
   </tbody>
 </table>
@@ -47,4 +51,5 @@ This feature is neither targeted at, nor implemented in, browsers.
 
 ## See also
 
-- The HTTP [`TRACE`](/en-US/docs/Web/HTTP/Methods/TRACE) method
+- {{HTTPMethod("TRACE")}} method
+- {{HTTPStatus("405", "405 Method Not Allowed")}}

files/en-us/web/http/headers/nel/index.md

@@ -19,7 +19,7 @@ The HTTP **`NEL`** response header is used to configure network request logging.
     </tr>
     <tr>
       <th scope="row">{{Glossary("Forbidden header name")}}</th>
-      <td>no</td>
+      <td>No</td>
     </tr>
   </tbody>
 </table>