When attempting to restore a directory of backups on Virtualmin GPL 5.0.gpl, on Ubuntu, if the directory contains 'hidden' files (that is files that begin with .) the GUI will give an error indicating that the dot file is not a proper backup file.
Ideally, the restore process would ignore any .files that are in the folder, or at the very least common ones such as .bashrc, .cache, .profile, .bash_logout, etc that might be found in a user's home directory on various linux flavors. Or perhaps ignore them all and add a flag that won't ignore them for the rare occasion when you'd want them processed.
This is easy enough to work around by not foolishly using a user's home directory for backups, but could still easy confuse some users.