Yes. That that’s not clear to whoever came up with the names at Xojo makes me shake my head in disbelief.
And I agree that AppleScript gets this wrong, too. Though, as an excuse, back in the early 90s disks were still near-equivalent to volumes, though even then the term volume was already clearly defined and used. Still, shame on them, too, for this misnomer.
Besides that, the “normal” way to get the volumes on a Mac would be to use mountedVolumeURLsIncludingResourceValuesForKeys:options: | Apple Developer Documentation with the NSVolumeEnumerationSkipHiddenVolumes option.
However, that doesn’t unify or sort out the new volume types since Catalina and Big Sur. The first error in Xojo’s implementation seems to be that they do not suppress the hidden volumes, unless you can test the hidden property and sort them out yourselves (that’d be the better solution as long as it’s documented to be aware of that)?
The more annoying part is that eben with the NSVolumeEnumerationSkipHiddenVolumes option you’ll get the extra volumes on Big Sur that you surely are not interested in and that the Finder hides to the user. In a way, to support low level functionality, it would still be useful if Xojo would return them, but then Xojo needs to provide a way to determine their new volume types that tell you whether it’s part of a Volume Group, and of which kind.
I must admit that I have not figured out how to tell them apart myself, yet. Does someone know which API to use to get the Volume Group identifications?