iMovie Trash location.

In iMovie on Sequoia I found that deleted Projects and Events are located in __Trash folder.

Show package contents of the iMovie Library. In __Trash folder you can find deleted Projects and originals of the events.

However the file names appears with extra suffixes. They can be recovered by deleting ending of the file names up to the correct file extension.

The above recovery procedure is for individual project/event. If the whole library needs to be restored then

the following approach should be used.

In Finder navigate to the following folder

~/Library/Containers/iMovie/Data/Library/Caches/iMovieBackups

The path, folder names may vary depending on MacOS release.

When you get there you will see a list of previous backups of your iMovie library.  Select one and open in iMovie.