Read from the World of Warcraft client build files (JournalEncounterItem, JournalEncounterCreature, Achievement) and the Blizzard Game Data quest API.
How Matriarch's Shadowveil Compares
Who It Suits
Cloth is the armor type Mage, Priest and Warlock wear. With Intellect, Matriarch's Shadowveil suits Discipline, Holy and Shadow Priest; Arcane, Fire and Frost Mage; Affliction, Demonology and Destruction Warlock.
Transmog Sets
Matriarch's Shadowveil is part of the transmog set Eternal Curator's Vestment (Priest, Mage and Warlock only). The other 16 pieces:
Blizzard numbers items as they are created, so the named items next to ID 161401 (161396 to 161406) were usually added in the same batch as Matriarch's Shadowveil: the same quest line, zone, vendor or reward set.