Expects a document whose root is a ‘GrandWrapper’ carrying a handle dictionary in the 6-column form left behind by handles_grand_wrapper_substitute:

handle=|||||used handle=|||||

Emits one DesugaringWarning per handle whose ‘used’ column is empty and whose id points to a node whose tag is listed in the param, blamed on that node. (Passing [“MathBlock”] therefore reports unused equation handles.)

Handles on nodes of any other tag are silently ignored, as are ids that no node carries.

Leaves the tree unchanged; must run before the GrandWrapper is unwrapped.