Druid ability · learned at level 18 · Nature

Faerie Fire Rank 1

Faerie FireRank 1

55 Mana30 yd range

Instant

Decrease the armor of the target by 175 for 40 sec. While affected, the target cannot stealth or turn invisible.

Game files · build 1.60.1.70245Read from the WoW Forever beta client, build 1.60.1.70245.

In Blizzard's notes

What Blizzard said about Faerie Fire, each line checked against the files.

Matches the files
Faerie Fire no longer resets your swing timer when used.
The files Build 70170 removed the interrupt row (InterruptFlags 8, the auto-attack flag) from all four Faerie Fire ranks (770, 778, 9749, 9907).
Faerie Fire Faerie Fire Faerie Fire Faerie Fire Development Notes, October 1
Not in the files
Multiple debuffs like Faerie Fire and Demoralizing Shout don't cause threat.
The files Known threat issue; threat is computed by the server.
Demoralizing Shout Faerie Fire Development Notes, October 1
Partly
Faerie Fire: Now castable while shapeshifted into Bear Form, Cat Form, or Dire Bear Form, costing no resources, but gains a 6 second cooldown.
The files Faerie Fire can be cast in Cat, Bear, Dire Bear and Moonkin Form in 70245 (shapeshift mask 0x40000091; Classic allowed Moonkin only). The client still lists the full mana cost (115 at rank 4) and no cooldown, so the free in-form cast and the 6 sec cooldown aren't in the files.
Faerie Fire Faerie Fire Class deep dives: Hunter and Druid