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Eliminate Empties: Remove superfluous empties in the imported scene,
Merge Rigs: Merge all selected armatures with the active one.
Merge Toes: Merge the individual toe bones with the main toe bone. Useful if you don't need to control the individual toes separately, e.g. if the character wears shoes.
Copy Pose: Copy the pose from the active armature to selected armatures.
Apply Rest Pose: Apply the current pose as rest pose for the selected armatures and their child meshes.
Apply Active Shapekey: Add active shapekey to all other shapekeys.
Change Armature: Change the armature modifier of selected meshes.