Apologies, by persist I meant just beyond the end of that run of the software (i.e. the software itself couldn't manage/delete the files), to see what went "wro

Apologies, by persist I meant just beyond the end of that run of the software (i.e. the software itself couldn't manage/delete the files), to see what went "wrong". Deleting at reboot is perfectly fine. /var/run "This directory contains system information data describing the system since it was booted" which doesn't seem to fit my use case that well. Not to say there isn't another directory that does fit, but I haven't found it.