What does Tiger Mastery reward?

No reward has been recorded for Tiger Mastery yet.

Where does Tiger Mastery start?

Ajeck Rouack in Stranglethorn Vale offers it.

The quest log lists it at level 35.

No. The quest exists in Classic Era as well.

World of Warcraft: Forever · quest · level 35

A level 35 quest in World of Warcraft: Forever, offered by Ajeck Rouack in Stranglethorn Vale. Recorded by 1 player running the addon.

Pay shows once a player with the addon opens the quest.

No reward item has been recorded for this quest. The offer window fills this in when a player with the addon opens it.

What does Tiger Mastery reward?: No reward has been recorded for Tiger Mastery yet.
Where does Tiger Mastery start?: Ajeck Rouack in Stranglethorn Vale offers it.
What level is Tiger Mastery?: The quest log lists it at level 35.
Is Tiger Mastery new in WoW Forever?: No. The quest exists in Classic Era as well.

What sells at this level, and what to keep from these rewards, is in the level 30 to 40 gold guide.

Source: what players running the addon saw in the quest windows; the quest text itself stays in the game. Every quest seen · Stranglethorn Vale