From Guild Wars 2 Wiki
After completion: You now gain bonus rewards from Chests of the Mists and Fractal Encryptions. Mist potion conversion has improved.
— In-game description
- Increases the value of junk items in Unlocked Fractal Encryptions from ~25s/chest to ~43s/chest on average, the chance of a key from ~7.5% to ~10%, and also the amount of +1 Agony Infusions.
- Fractal potions will now grant you 25% of your AR per stack in bonus stats.