Just a suggestion, to add an entry on the list of the scheduled backups, in virtualmin, to immediately inform the reader of when the next backup is going to take place.
Crontab reading isn't one of my skills and entries such as " Yes, at cron time 1 6 6,14,21,29 * *" or "Yes, at cron time 0 * * * 2" mean nothing to me. I suspect it would be an interesting addition, to add an entry below this "yes at cron time..." line, telling in human-readable language when the next backup will take place.
It could take the form of a checklist if() sort of thing. If it's in less than one hour, give the answer "in x minutes". If else, if the backup is in less than a day, give the answer "in x hours", if else give the answer "in x days".
Screenshot for example, with random human-readable information, as they were I didn't bother translating what those cron lines meant.
Hope the suggestion didn't bother, have a good day!