The game's collection data lists Bubblebrew Leggings as sold by 2 vendor NPCs in Warspear and Stormshield.
Vendor
Zone
Map
Waypoint
Other items it sells
NPC #86382
Warspear
-
-
15
NPC #86391
Stormshield
-
-
15
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.
How Bubblebrew Leggings Compares
Who It Suits
Cloth is the armor type Mage, Priest and Warlock wear. With Intellect, Bubblebrew Leggings suits Discipline, Holy and Shadow Priest; Arcane, Fire and Frost Mage; Affliction, Demonology and Destruction Warlock.
Transmog Sets
Bubblebrew Leggings is part of the transmog set Breezebinder's Vestments (Priest, Mage and Warlock only). The other 16 pieces:
Blizzard numbers items as they are created, so the named items next to ID 92873 (92868 to 92878) were usually added in the same batch as Bubblebrew Leggings: the same quest line, zone, vendor or reward set.