What exactly does the Clean-up button in Themes do? I found no reference in the DO manual.
It deletes unused stuff. Just click it to find out; it'll tell you what it's about to do before anything happens.
Rejoice that you have nothing that needs cleaning up?
There's no way to control what get's deleted? Just everything older than a week?
In my case, it's this:
where clicking 'show me' shows a lister with the collection that holds images that it wants to delete. Basically, images that aren't being used by Dopus but are stored in /dopusdata.
The '9 old backup themes' are just backups of theme-settings that were auto-saved when I selected a different theme. The ones shown in 'backup' in the theme windows.
Not sure what else there is, I think I saw some more stuff once. Best way to discover them is to play around with your settings. Which you should do anyway, to learn about all the Dopus settings and possibilities.
There's a separate checkbox for deleting more recent backups, if any exist.
I had one checkbox either checked or unchecked deleting everything older than 7 days. I can't magine why 7 days? That kind of implies you have backups younger than 7 days of your current theme and somehow it's getting backed up on some schedule but it wouldn't be true in my case.
Sure I do backups of my entire system but that's a bit more trouble than always having a current backup here.
The backup happened because I made it happen by applying a new theme. That's the only time theme backups are created automatically. There's no scheduled backups for themes.
The clean-up UI separates recent and old backups because you're more likely to need the recent ones, and less likely to still need the old ones.
The point of theme backups is that you may try out a theme and decide you hate it and want to go back to what you had before. If you've been using the new theme for a week, you probably don't need the old backup anymore (and probably won't remember what was in it, either).