Control-z is the universal "undo" keyboard shortcut for PC's.
It doesn't work in the new Publisher when you apply a rotate left or right to a selected vector object.
Yes, you can effectively undo it by right clicking on the object and select reset rotation, or rotate in the opposite direction,
but Control-z should also work.
ALSO, PLEASE make the topics SEARCH-ABLE ! It is a waste of time looking through 15+ pages of posts to find your issue.