The clipboard does not work on "firefox on wayland".
1. Open "Firefox on Wayland"
2. Copy or cut some content
3. Try to paste it outside "firefox on wayland" on a application like gedit.
Have the paste
The clipboard is empty
Note that the reverse (from XWayland apps to firefox on wayland) works!
I can confirm this one. Happens for both page content and the address bar.
*** This bug has been marked as a duplicate of bug 1585393 ***