Linux Firefox works, FreeBSD Firefox broken (discord)

TLDR: Audio chat on discord works on linux (emulated) firefox, Broken on
native Firefox.

OK.  So this is a FreeBSD-15.0 desktop.  And audio is working here --- this
is something at application or network level --- and by finding the linux
binary to work, I think it gets interesting.

I previously posted this bug to -stable, but this seems more hacking, now.

I've actually tested Firefox, Chromium and unGoogledChromium on FreeBSD.
All broken --- they fail to connect to the audio chat.  I think discord is
using QUIC packets, but then there also seems to be 2-way traffic in QUIC,
so I'm not sure it's the problem.

This all started about a week ago... and I can pin it down there as our D&D
group uses the discord audio chat often.

To test: open discord (discord.com) and use the web app, not the binary app
(afaik, that's not available natively), go to a "server" that has an audio
chat.  The FreeBSD discord has a few.  Try to join the chat.  If it's
always a yellow "connecting" or other yellow message, you fail  "Connected"
in green is a good message.