Finality's Auger

• The base order: Sundered Doctrine clears on your account until Finality's Auger drops.
• Add Catalyst: the catalyst, which the game lists as acquired in Sundered Doctrine, is collected as well.
• Add Catalyst + Masterwork: the catalyst is also completed so the rifle becomes a Masterwork; its unlock task is defeating targets with Finality's Auger.
• Self-play (Sherpa): you play the runs together with the team.

A booster usually starts within about 30 minutes. The finish time is flexible: an Exotic drop needs an unknown number of clears, and the Masterwork extra adds the catalyst kills on top.

Its intrinsic perk, Ruinscribe's Forge, turns the alternate weapon action into a launcher: one special projectile, costing three rounds of ammo, puts down a Ruinscribe Turret that fires on nearby enemies by itself. The perk text advises aiming the projectile upward so the turret gets open sight lines. The second trait, Ruinscribe's Beacon, works while a turret is out: the rifle swaps between normal fire and laser fire, and targets hit by the laser are marked, so the turret turns to them before anything else and hits them with stronger munitions. Barrel, battery and stock are fixed: Arrowhead Brake, Particle Repeater and Short-Action Stock.

• The Final Shape Dungeon Key, because the rifle drops in Sundered Doctrine. All Dungeon Keys are part of Destiny 2: The Collection or sold in Eververse.
• For either catalyst extra: The Drowning Labyrinth quest finished on the account, which the service asks for.

Where does Finality's Auger come from today?

From Sundered Doctrine, which Bungie still lists among the available dungeons; the Collections entry names it as the source.

What does the catalyst change?

It upgrades the rifle to a Masterwork. The catalyst text speaks of enhanced capabilities such as higher stats or extra perks.