What does Chen's Empty Keg reward?

Chen's Empty Keg gives Stormstout outright, 1,100 experience.

Where does Chen's Empty Keg start?

It was picked up in The Barrens.

Its level has not been recorded yet; it shows once a player accepts it with the addon running.

No. The quest exists in Classic Era as well.

World of Warcraft: Forever · quest

A quest in World of Warcraft: Forever in The Barrens and turned in to Brewmaster Drohn. Recorded by 1 player running the addon.

Level, giver and objectives show once a player with the addon accepts the quest.

Item	Given	Item level	Vendor sell
Stormstout	outright	15	63c

What does Chen's Empty Keg reward?: Chen's Empty Keg gives Stormstout outright, 1,100 experience.
Where does Chen's Empty Keg start?: It was picked up in The Barrens.
What level is Chen's Empty Keg?: Its level has not been recorded yet; it shows once a player accepts it with the addon running.
Is Chen's Empty Keg new in WoW Forever?: No. The quest exists in Classic Era as well.

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