This is the best summary I could come up with:

Two years ago, at Quake Con 2021, id Software and Nightdive Studios shadow dropped a remaster of the original Quake which was critically acclaimed for its features and meticulous polish.

Two years later, id Software and Nightdive are at it again with an enhanced version of Quake II, available now for all platforms and the best part is that, if you already own Quake II on Steam, it's a free update.

Quake II is currently listed as  Playable on Steam Deck, although that rating is from the original version so needs Valve to re-review it.

Includes the original Quake II campaign plus both Mission Packs, The Reckoning, Ground Zero, plus the previously Nintendo 64-exclusive Quake II 64 and the brand-new Call of the Machine episode from MachineGames.

Play local split-screen and online across four Multiplayer modes with crossplay functionality:

Additional Editor note from Liam Dawe: giving it a run on Steam Deck with Proton 8 - it works out of the box.

I'm a bot and I'm open source!