[jtth]

(Side note: what the hell is that website trying to do to my computer? It's trying to open so many connections on weird ports!)

[showerst]

Looks like they're using a bunch of websockets for something. Probably that live player count up in the navigation.

[ornicar]

lichess opens only one websocket connection, on a port between 9021 to 9029. That port range prevents a weird behavior on firefox when the connection is interrupted.