Right, but presumably the Doom and Quake server code was written by id Technologies themselves. That's not the case with a lot of modern multiplayer games. They license middleware like Photon Engine and don't have the rights to redistribute the server software, even in binary format.
I guess they could just strip our the parts of the server code that they don't have the rights to redistribute, but then it wouldn't be functional.
Right, but presumably the Doom and Quake server code was written by id Technologies themselves. That's not the case with a lot of modern multiplayer games. They license middleware like Photon Engine and don't have the rights to redistribute the server software, even in binary format.
I guess they could just strip our the parts of the server code that they don't have the rights to redistribute, but then it wouldn't be functional.