If it’s on your Mac but you can’t find it, try using finders search by file extension feature:
The file extension varies by RW release, you haven’t said what version you are using.
This feature also should work with TimeMachine, so you search your backups
If you didn’t turn on the backup feature of publishing (it’s off by default) then you need to find it on your Mac, on your old Mac or from a backup like TimeMachine.