It’s an option when you add a new folder and choose trash can file versioning. I haven’t seen it before, and the text below the field says
The interval, in seconds, for running cleanup in the versions directory. Zero to disable periodic cleaning.
…but I don’t quite understand it. Can someone give an ELI5?
The default setting, i.e.
means that Syncthing will check every 3600s (=1h) whether there are files to be deleted from the .stversions folder.
However, this will only delete actual files if you set a specific number of days, as follows.
The default value of 0 means that files will be kept in .stversions with no time limit. A value of 1 would mean that Syncthing will delete files older than 1 day, and so on.
The purpose of this setting is mostly for setting a very large interval when you have folders that are always idle, in order to let disks spin down. (In cases where disks spin.)
