Druid talent · row 5 of Restoration, from level 30 (25 with Talented 5/5) · Physical

Improved Tranquility

Reduces threat caused by Tranquility by 50/100% and its cooldown by 30/60%.

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

Compared with Classic

Classic tooltip

Reduces threat caused by Tranquility by 50%.

Data	Classic	Forever
effect 2	none	added
effect 1 value	-50	-100

What Blizzard said about Improved Tranquility, each line checked against the files.

Matches the files
Improved Tranquility: Now also reduces the cooldown on Tranquility by up to 60%.
The files Improved Tranquility (17123) added a 30/60% cut to Tranquility's 5 min cooldown and keeps the 50/100% threat cut.
Improved Tranquility Tranquility Class deep dives: Hunter and Druid

69876 Sep 16First beta build we archived. No changes in the client files since.