Who is Mike Ornstein, and who does he work for?

M.O. has been here for a decade plus. This is nothing new.

It's only a "big" deal now because he's not an official team employee thus technically he shouldn't have been allowed in the facility this season due to COVID protocols, but he likely wasn't doing anything different than he hasn't been doing the last ten years.

After what he had done prior to these last ten years, why is he even allowed in the building?