#10 - April 27, 2016, 7:09 a.m.
It's one of the new transmogs although I'm not sure why it won't salvage.
Indeed, this is one of the new transmogrification items! As for why it can't be salvaged, the reason is two-fold. We made a conscious decision to disallow salvage to a) ensure the item isn't accidentally salvaged and you have a moment to recognize you've found something rare and b) to avoid a case where these items become go-tos for farming crafting materials (as that's not their intent).
Of course, there's no need to hang onto the item once you've unlocked its visual, since the transmog will remain available through the Mystic, so they can be vendored if you need to do some spring cleaning.
*Edit* Corrected the location of transmogs at the Mystic.