I have tested this item ✅ successfully on d1cbbed

Unfortunately this change also affects other pages than the home page.

On a copy of my homepage updated to 4.0 RC 2, I get https://test7.richard-fath.de/de/music/ for a categroy list with this PR applied, and not https://test7.richard-fath.de/de/music.html like it is on my J3 homepage or on the J4 copy without this PR.

That's why we should not be relying solely on human tests and should have automated testing

I have tested this item ? unsuccessfully on d1cbbed

See my previous comment.

For other testers: It's not enough just to test the home pages which have the issue. If such changes are done with the router, it needs to test other pages, too.

@richard67

For other testers: It's not enough just to test the home pages which have the issue. If such changes are done with the router, it needs to test other pages, too.

Test instructions by @brianteeman:

For human testing
Create a multlingual site and check that the urls for the home pages are correct
Test with both suffix enabled and disabled.

@sandramay0905 Sorry, did not want to blame you or anyone. Only wanted to say sometimes it needs to test a bit more than instructions say.

@sandramay0905 P.S. ... and thanks a lot for your testing activities in general. It really helps us a lot and is much appreciated.

without automated tests and documentation of how the urls are supposed to work its virtually impossible

Alternative PR is #34558 . It will be ready for test soon.

Update: No, doesn't work (yet).

Update 2: Now it works. I only don't know if my PR is the right way to fix the issue.