This indicates the versioning. It is the 11th hair model in a library, and "Var" suggests it is a variation (perhaps a different texture, length, or accessory) of the base model.
: Specifies the clothing layer or placement designation, meaning this particular mesh file interacts or anchors directly onto the upper torso/head armature of the character model. Technical Implementation in 3D Environments dnaddrkumikodualhorsetailhair011var top
Need help identifying another cryptic mod filename? Bookmark this guide and follow the same segmentation method: author → character → item type → variant number → component. This indicates the versioning