On my system, I have various XCompose definitions, such as
<Multi_key> <apostrophe> <a> for á
<Multi_key> <asterisk> <D> for Δ
<Multi_key> <E> <equal> for €
Multi_key> <plus> <minus> for ±
<Multi_key> <minus> <n> for –
These all worked in Firefox 154.0.1-1, but no longer work in 155.0-1,
whether in the address bar, search bar, or a textarea in a page.
I've tested this with fresh profiles, extracting
firefox_154.0.1-1_amd64.deb to a temporary directory and running
./usr/lib/firefox/firefox-bin --profile /tmp/x/ff/profile --new-instance
(which runs 154, confirmed via Help > About Firefox) versus
/usr/lib/firefox/firefox-bin --profile /tmp/x/ff/profile2 --new-instance
(which runs 155, confirmed via Help > About Firefox).
On the other hand, <Multi_key> <P> <o> <o> that I have for 💩 does still
work.
Copy-pasting the characters does still work.
I don't know if this is specific to Debian or exists upstream. If the
latter, please forward it there. 🙂
I set the severity on this report as "important", since being able to
enter characters like `á` or `€` from the keyboard is at the least a
major effect on the usability of the package.