I noticed that the folder referenced in the subject line is taking up 1.5 GB. Can I run the below to clear it without causing permanent damage to my system?rm -rf /var/cache/PackageKit/metadata/updates/packages/*
Fedora 23 -- Can I safely delete files in /var/cache/PackageKit/metadata/updates/packages?
disk usage
From the discussion in the bug linked in Daniel Bruno's answer .. you can get rid of these files using PackageKit console client pkcon$ sudo pkcon refresh force -c -1It takes some time but is provided by PackageKit itself. (and you may set a cron job for it)from the man page of pkcon(1)   refresh [force]       Refresh the cached information about available updates.and   -c, --cache-age AGE       Set the maximum acceptable age for cached metadata, in seconds. Use -1 for 'never'.So this tells PackageKit to delete cached information (refresh cached information with maximum acceptable age of : never)References :https://bugs.freedesktop.org/show_bug.cgi?id=80053#c6https://bugzilla.redhat.com/show_bug.cgi?id=1306992#c10