Warrior talent · row 1 of Protection, from level 10 (5 with Talented 5/5) · Physical

Improved Bloodrage

Increases all the Rage generated by your Bloodrage ability by 25/50%.

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

Compared with Classic

Classic tooltip

Increases the instant Rage generated by your Bloodrage ability by 2.

Data	Classic	Forever
effect 1 aura	aura (107)	aura (108)
effect 1 value	20	50

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

Matches the files
Improved Bloodrage moved to Row 1 (Was Row 2).
The files The Oct 2 server hotfix (read from the 70245 client cache) moved Improved Bloodrage's node (105974) from row 2 to row 1 (PosY 2730 to 2130).
Improved Bloodrage Development Notes, October 1
Matches the files
Improved Bloodrage moved to Row 1 (Was Row 2).
The files It moves from row 2 to row 1 in the 70245 hotfix (PosY 2730 to 2130); the same hotfix drops Last Stand's Improved Bloodrage requirement.
Improved Bloodrage Last Stand Warrior updates, October 2
Matches the files
Improved Bloodrage: Now increases initial Rage and Rage over time, instead of just initial Rage.
The files Classic added 2/5 instant Rage; 70245 raises all Rage from Bloodrage by 25/50% (aura 107 to 108, spell 12301).
Improved Bloodrage Class deep dives: Priest and Warrior

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