About a week late to post this but someone could probably use this info.
This is a community made patch to fix serious issues playing Black Ops 3 online everything from stuttering in menus to RCEs, it’s basically a requirement even if you’re just playing zombies with friends.
The latest version no longer requires you to run an exe along side the game and is officially supported on Linux now.
Does it require linking to an Activision whatever when you play it from Steam?
Nope just Steam
Excellent, may need to pick this up for a few friends.