A passive upgrade to the already potent Advent Hangar, unlockable through research. This allows the Advent Hangar to passively heal nearby units 4 shield points a second. This bonus does not seem to stack with other hangars Shield Bestowal ability
A player might think that this upgrade would be of little significance, but an extra four hitpoints a second will be very significant in long engagements. In short, brutal attacks this upgrade is trivial, considering that most units do not last long once the full attention of the fleet is on them. For countering AOE weapons, this can be very critical. For example, the Advent's Destra Crusader's Vengeance passive ability is completly canceled out by this passive ability of the Hangar.
It's worth noting that Strike Craft have no shields, and therefore are unaffected by this ability. In order to patch a mangled Anima, you have to dock it untill it's fixed/