Arch Linux

As described on task #53195, Mozilla will drop alsa support when version 54 will be released.

apulse package available on aur seems to be a working solution.

I would suggest to adapt firefox package as following for v54 and later:

adding it as optional dependence:

optdepends=(....
'apulse: ALSA support')

editing /usr/bin/firefox:

package() {
...
# Install a wrapper to avoid confusion about binary path
install -Dm755 /dev/stdin "$pkgdir/usr/bin/firefox" <<END
#!/bin/sh
if [ -x /usr/bin/apulse ]
then
exec /usr/bin/apulse /usr/lib/firefox/firefox "\$@"
else
exec /usr/lib/firefox/firefox "\$@"
fi
END
...
}

and editing /usr/share/applications/firefox.desktop:

[Desktop Entry]
...
Exec=/usr/bin/firefox %u
...
[Desktop Action new-window]
...
Exec=/usr/bin/firefox --new-window %u
...
[Desktop Action new-private-window]
...
Exec=/usr/bin/firefox --private-window %u
...

or if you do not want to do so, I should add help in wiki with adding those files in /usr/local/bin/firefox and $HOME/.local/share/applications.

What's your opinion?