Returns whether a unit allows all players on its threat list to receive kill credit. Used to override the normal "tapping" behavior for certain mobs -- if this function returns 1, the player does not have to be the first to attack the mob (or in the same party/raid as the first player to attack) in order to receive quest or achievement credit for killing it.

In the default UI, this function can prevent the graying of a unit's name background in the TargetFrame and FocusFrame even if the unit is otherwise tapped, indicating that kill credit is still available if the player attacks.