Don't use starting period to identify files to be deleted

Thanks for suggesting this new feature. I wonder what should be wrong with "hidden" files due to their leading period in the filename. The exported files are not supposed to be processed by any human, but by some process that's doing "the right thing" with them. And such processes shouldn't care about the OS display policy of such files. Or am I missing a use case where this is still important?

Having said that, using a different prefix could be implemented, but only as a configurable option with the current prefix, i.e. the period, as the default value. If anyone wanted to provide a merge request with such an implementation, I'd be happy to review and test this.