Accidentally overwrote a library. Can't find the older version now.

Where would FCP have backed up previous libraries?

I was trying to clean up my finder folders - saw there were 2 versions of the same library. One was old with very little in it which had the suffix .fcpbundle.

The one I'd been working on and wanted to save had no suffix.

I meant to replace the one with the suffix (the earlier one), but accidentally replaced the new one and now the files are nowhere to be found.

The new one should have been making backups somewhere but I can't find them.