I've upgraded to macOS Catalina and gone back to BaseCamp to store my tracks and waypoints since HomePort will never be 64-bit, I guess.
I've got everything restored to the way I had it previously, but I got to thinking:
I'd like to resurrect some of the detail missing in some of my saved tracks (date and time, elevation data) which had been lost a while back when doing a previous import and not paying attention to the loss of some of the data in the process. It's not a crisis, but many of my tracks from prior to 2011 or so are missing this information and I am hoping that there is a way to go back into the Database folders of previous versions of BaseCamp to find them and recover these missing details.
Digging into the 7 folders for my version history via Finder > Go > Library > Application Support > Garmin > BaseCamp > Database > [folders 3.3, 4.0, 4.1, 4.2, 4.5, 4.6, 4.8] > TrackSegments reveals thousands of files such as 'F38154AC-6579-44C8-AE63-429F2460AF86' in each folder. (Right off, it seems a daunting task as there is no track identifying information in the file name...)
Temporarily renaming older folders to '4.8' (the current version) did not work; the resulting My Collection was completely empty.
Trying to point to one of the older folders within BaseCamp to choose a new library did not seem to lead to the proper Database folder location; trying Preferences > Advanced > Choose New Library > Macintosh HD > Library > Application Support does not show an enclosed Garmin folder.
Again, it's not a crisis, it just seems to me that I had somehow been successful at something similar in the past.