What does Twilight Falls reward?

Twilight Falls gives Nimbus Boots, Heartwood Girdle outright, a choice of Nimbus Boots, Heartwood Girdle, 6,050 experience.

Where does Twilight Falls start?

Argent Guard Manados in Darnassus offers it.

The quest log lists it at level 25.

No. The quest exists in Classic Era as well.

World of Warcraft: Forever · quest · level 25

A level 25 quest in World of Warcraft: Forever, offered by Argent Guard Manados in Darnassus. Recorded by 16 players running the addon.

Item	Given	Item level	Vendor sell
Nimbus Boots	outright	25	7s 74c
Heartwood Girdle	outright	25	6s 50c
Nimbus Boots	as a choice	25	7s 74c
Heartwood Girdle	as a choice	25	6s 50c

What does Twilight Falls reward?: Twilight Falls gives Nimbus Boots, Heartwood Girdle outright, a choice of Nimbus Boots, Heartwood Girdle, 6,050 experience.
Where does Twilight Falls start?: Argent Guard Manados in Darnassus offers it.
What level is Twilight Falls?: The quest log lists it at level 25.
Is Twilight Falls 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 20 to 30 gold guide.

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