The game's collection data lists Daybreaker Helm as sold by 2 vendor NPCs in Tanaris and Dalaran. The first vendor stands at 51.3, 28.2 on the Tanaris map.
Vendor NPC, zone and position come from the client's collection source tables (CollectableSourceInfo and CollectableSourceVendorSparse); coordinates are the in-game map readout.
Build history
First seen in build 5.5.4.69585 (Mists of Pandaria).
Read from the World of Warcraft client build files (JournalEncounterItem, JournalEncounterCreature, Achievement) and the Blizzard Game Data quest API.
How Daybreaker Helm Compares
Who It Suits
Plate is the armor type Death Knight, Paladin and Warrior wear. With Strength or Intellect, Daybreaker Helm suits Arms, Fury and Protection Warrior; Holy, Protection and Retribution Paladin; Blood, Frost and Unholy Death Knight.
Transmog Sets
Daybreaker Helm is part of the transmog set Magma Plated Battlearmor (Death Knight only). The other 16 pieces:
1 other item in the current build is also called Daybreaker Helm. Same-name entries are usually a different rank, faction, quest stage or reward track of the same object.
Blizzard numbers items as they are created, so the named items next to ID 63531 (63525 to 63536) were usually added in the same batch as Daybreaker Helm: the same quest line, zone, vendor or reward set.