This is the premise of the new campaign, as written on the blog post announcing the update:

As the battle-hardened Ranger, players survive a labyrinthine dimension where time folds back onto itself, creating a unique looping structure where each visit in the present reshapes the future.

Collect runes to unlock previously sealed paths brimming with new routes, encounters and secrets, plus persistent health and ammunition upgrades throughout add a new layer of progression to Quake’s classic gameplay.

The new maps have been added to the campaign list in the remastered version of Quake, and like that remaster, they’re available free to anyone who already owns Quake on Steam, as well as Quake on current and last-gen PlayStation, Xbox, and Nintendo consoles.

It has recently been reported that a significant number of people at original Quake developer id Software were laid off amid Microsoft’s major Xbox reorganization; however, most of that studio has been more focused on the recent Doom reboot series. MachineGames has been the primary force generating new Quake content, and that studio does not appear to have been as deeply affected by layoffs just yet—though more are expected throughout the Xbox organization in the coming months.

The grim context aside, it’s good to see some classic PC games still getting new maps all these years later. Like Age of Empires II, Quake has seen something of a resurgence thanks to its remaster and more official content over the past few years.