I raised this question quite some time ago but received no responses.
I'm running JabRef 3.3 (stuck there because of the oft-discussed groups problem) and have seven databases. When I explicitly back a database up (C-s), the database is saved as a /tmp/jabref*.tmp file. When I back the database up again, the old .tmp file is overwritten by the new one.
However, exactly every five minutes three of my seven databases are automatically backed up to a file named /tmp/jabref*.save.bib. This occurs even though no operations are being done with JabRef such as a Save command. Because there is no automatic deletion of these files each time there is a new save, they accumulate to the point it fills my 20 Gb /tmp directory.
It seems the three databases are configured differently, but I find no difference. In the Preferences for all seven I have checked Backup old file while saving. I don't know of any JabRef automatic backup system that runs every five minutes. I checked /var/log/chron.log and there is no cron job doing it. I could write a script to delete these .save.bib
files automatically, but I'd rather address the source of the problem.