I’m honestly not sure. there’s a call icon below the message input box that generates at Jitsi meet link when clicked, however there doesn’t seem to be much integration than that. There’s no indicator that shows there’s a Jitsi meeting going on on Zulip side. My friends frequently use Discord’s voice chat feature to see if there’s anyone already in the room and whether they’re sharing screen/mic on, so this is a quite necessary feature.