This skill should act as a mastery for the spells regenerate rift entity and dimensional leech, allowing more effect per spell point spent.
The in game help reads:
Skill duration: random. Type of skill : automatic skill (arcane skill). Affecting stats: None. It uses no endurance points. The flow of energy from the rift worlds is difficult to manipulate and direct. This skill not only increases the amount of energy available to the riftwalker, it also allows the energy to be more accurately focused.