How does the third mod slot in Outriders Worldslayer work?

Outriders Worldslayer is a new expansion for the 2021 co-op third-person shooter by Bulletstorm and Painkiller developers People Can Fly. It adds more than a second campaign and features plenty of new gameplay details.

Outriders Worldslayer's new update introduces Apocalypse Weapons with a third mod slot. Apocalypse Items have a variety of new features and are enhanced Epic or Legendary items. The third slot is randomly assigned from a small, specialized group of options. It works similarly to weapon pulls in Destiny 2. In the game, weapons and armor have two mod slots, one of which can be selected and the other fixed.

The third mod slot in Outriders Worldslayer is a random benefit, but it's still better to have it. The expansion is not trying to fix the elements of the original game that struggled, it is an expansion that adds more to the experience.