According to upstream, only problem is removal of cgi support in python 3.13, this affects only a tests and would be fixed by upstream vendoring required support: https://bugzilla.mozilla.org/show_bug.cgi?id=1907177 https://bugzilla.mozilla.org/show_bug.cgi?id=1936694 https://github.com/web-platform-tests/wpt/issues/39359
It's probably true, IIRC firefox-128esr has pgo broken with python-3.13 but thunderbird doesn't have working PGO so 3.13 is okay here. But I'd like to keep firefox-esr and thunderbird-esr ebuilds in sync. Next month thunderbird-136 will be released for wider use, and that's going to be based on firefox:rapid ebuild which has python-3.13 support already. So I'd like to wait for that instead of testing tb-128.7.0 again, since stabilization tests are already on the way.