Read from the World of Warcraft client build files (JournalEncounterItem, JournalEncounterCreature, Achievement) and the Blizzard Game Data quest API.
How Mardum Chain Pauldrons Compares
Who It Suits
Mail is the armor type Evoker, Hunter and Shaman wear. With Agility or Intellect, Mardum Chain Pauldrons suits Beast Mastery, Marksmanship and Survival Hunter; Elemental, Enhancement and Restoration Shaman; Devastation, Preservation and Augmentation Evoker.
Transmog Sets
Mardum Chain Pauldrons is part of the transmog set Darkwatcher Bindings (Hunter, Shaman and Evoker only). The other 16 pieces:
Blizzard numbers items as they are created, so the named items next to ID 134389 (134384 to 134394) were usually added in the same batch as Mardum Chain Pauldrons: the same quest line, zone, vendor or reward set.