api.fetch - Firefox is not compatible because does not fulfil the specification because of bug https://bugzilla.mozilla.org/show_bug.cgi?id=1629773

What type of issue is this?

Browser bug (a bug with a feature that may impact site compatibility)

What information was incorrect, unhelpful, or incomplete?

See - https://bugzilla.mozilla.org/show_bug.cgi?id=1629773

This is why Firefox does not support fetch as it is specified!

What browsers does this problem apply to, if applicable?

No response

What did you expect to see?

I expect to see that Firefox is not compatible!

Did you test this? If so, how?

Yes, I implemented a web application and when I close the browser or the last tab where my web application is running the fetch with keep alive set to true does not go to my server. But if there are more tabs and I close the tab with my web application, it goes correctly to my server.
This is clearly breaking the requirements of fetch and this is why Firefox must NOT be marked as compatible and fetch must NOT be described as "fully supported by most browsers". It simply is not!

Can you link to any release notes, bugs, pull requests, or MDN pages related to this?

No response

Do you have anything more you want to share?

No response

MDN URL

https://developer.mozilla.org/de/docs/Web/API/Window/fetch

MDN metadata

Start with the api.fetch compatibility report and compare its current Firefox data with the linked Firefox Bugzilla issue 1629773 and the MDN fetch page. Confirm the reported keepalive behavior and update the compatibility information so Firefox's support status matches the specification and observed behavior.