I just used --dry-run on --purge-broken-files and it purged for real, so there might be a generic problem here. Previously I think I tried it on a restore which involved folder creation, and later restores got upset because of lack of expected folders (or something like that). I’m sure it’s tough (and maybe not urgent) to cover all cases, however it’s also good to know what doesn’t work so that perhaps some regrettable advice isn’t handed out…