Read from the World of Warcraft client build files (JournalEncounterItem, JournalEncounterCreature, Achievement) and the Blizzard Game Data quest API.
How Desecrated Past Compares
Who It Suits
Leather is the armor type Demon Hunter, Druid, Monk and Rogue wear. With Agility or Intellect, Desecrated Past suits Assassination, Outlaw and Subtlety Rogue; Brewmaster, Mistweaver and Windwalker Monk; Balance, Feral, Guardian and Restoration Druid; Havoc, Vengeance and Devourer Demon Hunter.
Transmog Sets
Desecrated Past is part of the transmog set Tundraspite Armor (Rogue, Monk, Druid and Demon Hunter only). The other 16 pieces:
Blizzard numbers items as they are created, so the named items next to ID 40285 (40280 to 40290) were usually added in the same batch as Desecrated Past: the same quest line, zone, vendor or reward set.