Does JitsiMeet connect to JVB through 10000udp directly?

Does jitsi meet connect the jvb port 10000/udp through websocket?
if yes

  1. then What is the websocket connection through wss://jitsi-domain.tld/colibri-ws for?
  2. which part of the jitsi-meet code is responsible for that?

if no
then why does port 10000/udp have to be publicly open?

AFAIK, port 10000/udp is used for media traffic.

This is different from the websocket connection which is used for client-to-bridge messaging. See jitsi-videobridge/web-sockets.md at master · jitsi/jitsi-videobridge · GitHub

You don’t have to have websockets enabled, you can disable it from /etc/jitsi/…
The connection does not directly go through 10000, there must be a communication of some kind I guess.