What this means is that XDF disk images formatted as 80-track 23-sector-per-track images will work with XDF code that honors that format; however, I've not yet been able to test with "real" XDF disk images (ie, disk images created with DiskDump using the experimental --xdf flag). "Real" XDF disk images almost certainly need more work (eg, setting all the sector IDs properly), but the groundwork has been laid.
Without --xdf, DiskDump simply dumps an XDF disk image as a vanilla 80-track, 23-sectors-per-track disk image.
In addition, I regenerated all the PC-DOS 7.00 disk images without --xdf, to see if that works any better (it seems to work for VirtualBox)