New in version 10.3: The event was introduced to replace the Signal/Slot
The PSR-14 event
is triggered after a package has been deactivated.
This event is dispatched when an extension is deactivated in the Extension Manager, therefore starting with TYPO3 v11 this event is only dispatched in legacy installations, not in Composer-based installations. Use installer events by Composer for Composer-based installations.