This blueprint actor is used when attaching any item to the player pawn/ship. Even ones that are "non-existent" or invisible such as module upgrades or non visual changes. We spawn and attach this actor for every thing that modifies stats on the ship so that we can properly track what is modifying what stats.
This blueprint has two important items of note. The function SetSkeletalMesh and the variable AttachActorVariables
SetSkeletalMesh
This function is simply setting the SkelMesh skeletal mesh component to the incoming skeletal mesh. This is used when attaching an object to the player pawn/ship such as weapons/hardpoints.
AttachActorVariables
This variable is set when we attach any item to that modifies stats to the player pawn. It is used often and contains many different variables for the various stats that can be modified through items. This variable is a struct of the other item information structs, so if you want to add various stats of your own, you should add those to the relevant structs not the AttachActorVariables struct.