The Symbols panel menu's Reset Transformation and the Control bar's Reset
(shown while symbol instances are selected) give the selected instances
their symbol's own scale again, without rotation, shear or reflection, as
one undo step (symbol.instance.resetTransform). Each instance keeps the
center of its art's bounding box in place. Instances in perspective and
instances already at their symbol's scale are left as they are, no undo
step is added when nothing changes, and both controls are enabled only
while a selected instance would change.
Docs: docs/mcp.md, docs/target-app-parity.md.