Mobile Phase Detection is a passive ability that can be researched for the Serevun Overseer. Researching this requires five Lirtestra Weapons Labs, along with prerequisite research of Overseer Prototype. Its in game description is "Grants the Mobile Phase Detection Ability to Serevun Overseers, allowing them to detect enemy ships heading towards the gravity well the cruiser occupies." This ability becomes practically useless after researching Highly Attuned Sensors, but is helpful if you are focusing on the warfare tree. This ability results in "Phase Jump Detection Active."