Larian Studios Forums Divinity: Original Sin 2 - The Modding Dungeon Divinity - Original Sin 2 - Modding General Customizing Adrenaline Skill

I'm pretty sure the 100 is the chance of applying a status effect (in this case the Adrenaline effect), and the -1 is the duration of the effect (-1 meaning indefinite). I would guess that the 2's refer to the AP gained and lost but you would need to test to be sure.