Only the native Plex player is based on XBMC/Kodi, the Plex server and web player is and always has been proprietary. I also imagine the server is where they do stats collection.

OK, they could make it part of the TOS of their online service.

You know, the service you're giving information to in the first place.

No it isn't

Is https://github.com/plexinc/plex-media-player/blob/master/LIC... not the Plex source code repository?