[HTTP] Cross-Origin-Embedder-Policy: credentialless supported

[hamishwillee]

Acceptance Criteria

• The listed features are documented sufficiently on MDN
• BCD is updated
• Interactive example and data repos are updated if appropriate
• The content has been reviewed as needed

For folks helping with Firefox related documentation

• Set bugs to dev-doc-complete
• Add entry to Firefox release notes if feature is enabled in release
• Add entry to Firefox experimental features page if feature is not yet enabled in release

Features to document

I think just BCD for credentialless. Note, this is released on desktop only. Android is nightly only.

Related Gecko bugs

https://bugzilla.mozilla.org/show_bug.cgi?id=1851467

Other

• Check content open issues to see if any pertain to the subject matter. If there are any that can be closed because of the work, do so. If there are any that can be fixed relatively quickly because of the knowledge from completing this issue and you have time, feel free to go ahead and fix them.
• Check if glossary updates are required for the feature you're documenting - whether an existing term needs to be updated or a new term should be added.
• Check if BCD update means that content pages need to have experimental markup removed or deprecated markup added (front matter tags and macros).

[hamishwillee]

Status:

• BCD FF119 HTTP COEP header: credentialless supported on desktop browser-compat-data#20855
• Docs - already documented. The experimental flag should disappear automatically I hear on sync with BCD - see Cross-Origin-Embedder-Polic
  • Cross-Origin-Embedder-Policy - credentialless not longer experimental #29554
• Release note - Ff119 relnote coep cred #29414
• dev-doc-complete

Just waiting to see if https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cross-Origin-Embedder-Policy auto updates with removal of the experimental flag. If not will manually fix next week.