Add back standards position banner with agreed wording

files/en-us/glossary/web_standards/index.md

@@ -6,7 +6,7 @@ page-type: glossary-definition
 
 {{GlossarySidebar}}
 
-Web standards are rules established by international standards bodies and defining how the {{Glossary("World Wide Web", "Web")}} works (and sometimes controlling the {{Glossary("Internet")}} as well).
+Web standards are rules established by international standards bodies that define how the {{Glossary("World Wide Web", "Web")}} works (and which sometimes control the {{Glossary("Internet")}} as well).
 
 Several standards bodies are responsible for defining different aspects of the Web, and all the standards must coordinate to keep the Web maximally usable and accessible. Web standards also must evolve to improve the current status and adapt to new circumstances.
 
@@ -18,6 +18,14 @@ This non-exhaustive list gives you an idea of which standards websites and netwo
 - **Ecma Intl.:** scripting standards, most prominently for {{Glossary("JavaScript")}}
 - **{{Glossary("ISO")}}** (International Organization for Standardization): standards governing a diverse array of aspects, including character encodings, website management, and user-interface design
 
+## Opposing standards
+
+Occasionally, the members of a standards body may disagree with how a feature is developing, and some may **oppose** it. This means that technology implementers (for example web browser vendors) who disagree with the feature in its current form are unlikely to ever implement it.
+
+Vendors that _do agree_ with the feature usually still implement it so that it is available to experiment with and provide feedback on. This enables interested parties to build use cases and demonstrate the issues with the feature, hopefully working toward reaching a consensus on a future version.
+
+Standards body members often publish a record of their position on different standards, for reference. For example, see [Mozilla Specification Positions](https://mozilla.github.io/standards-positions/) and [WebKit Standards Positions](https://webkit.org/standards-positions/).
+
 ## See also
 
 - [Web standards](https://en.wikipedia.org/wiki/Web_standards) on Wikipedia

files/en-us/mdn/writing_guidelines/page_structures/banners_and_notices/index.md

@@ -48,3 +48,19 @@ In summary:
 - `\{{Non-standard_Header}}` — generates a **Non-Standard** banner that indicates that use of the technology is not part of a formal specification, even if it is implemented in multiple browsers.
   Also add `status` of `non-standard` to the page front-matter.
 - `\{{SecureContext_Header}}` — this generates a **Secure context** banner that indicates the technology is only available in a [secure context](/en-US/docs/Web/Security/Secure_Contexts).
+
+### Experimental: "Standards positions" banner
+
+Occasionally, browser vendors disagree on how a feature is developing, and some may oppose it in its current form. In exceptional cases, MDN documents technologies in this state to encourage the web community to experiment with them, provide feedback, and help browser vendors reach a consensus.
+
+It is important to clarify the current standardization status of such features to readers. While a longer-term solution for representing this information is not final, we are doing the following for specific high-profile technologies to avoid confusion:
+
+- Adding this banner to the landing page for that feature (not for every subpage for the feature):
+
+  ```text
+  > **Warning:** This feature is currently opposed by two browser vendors. See [Standards positions](#standards_positions) for details of opposition.
+  ```
+
+- Adding a "Standards positions" section to the same page as the above banner, as a sub-section of the standard "Specifications" section.
+
+> **Note:** See [Related Website Sets](/en-US/docs/Web/API/Storage_Access_API/Related_website_sets) for an example of the "Standards positions" section and what it should contain, as well as the landing page banner.

files/en-us/web/api/storage_access_api/related_website_sets/index.md

@@ -10,6 +10,8 @@ spec-urls: https://wicg.github.io/first-party-sets/
 
 {{DefaultAPISidebar("Storage Access API")}}
 
+> **Warning:** This feature is currently [opposed](/en-US/docs/Glossary/Web_standards#opposing_standards) by two browser vendors. See [Standards positions](#standards_positions) for details of opposition.
+
 Related website sets are a mechanism for defining a set of related sites that share trusted content. As a result, browsers will grant default access for these sites to [third-party cookies](/en-US/docs/Web/HTTP/Cookies#third-party_cookies) when they have content embedded in other set members.
 
 ## Concepts and usage
@@ -149,7 +151,7 @@ RWS has been designed with security in mind. It would be disastrous if a bad act
 
 ### Standards positions
 
-One or more vendors oppose this specification. Known positions are as follows:
+Two browser vendors [oppose](/en-US/docs/Glossary/Web_standards#opposing_standards) this specification. Known positions are as follows:
 
 - Mozilla (Firefox): [Negative](https://mozilla.github.io/standards-positions/#first-party-sets)
 - Apple (Safari): [Negative](https://webkit.org/standards-positions/#position-93)