Supermin builds very tiny appliances as described here:
To do this, it needs to have access to the original /etc files
[technically, any file marked %config by RPM] since those are the only
files that could be modified by the administrator, so those are the
only ones we need to save in the appliance at build time.
When not running under Koji, it gets these by downloading the RPMs
(using yumdownloader or the dnf equivalent), unpacking them and
extracting the /etc files it needs.
However this doesn't work when running under Koji because there is no
network access and no root access (so we can't just read the
unmodified files from /etc). This is of course as it should be.
Since Koji doesn't provide an official way to get to the pristine RPMs
that were used to build the buildroot, we grabbed them from the yum
cache. But since the move to dnf in Fedora Rawhide, this no longer
works as dnf defaults to keepcache=0 (which is not a great decision
for plenty of other reasons, but dnf upstream show no sign of changing
this despite many asking).
Anyhow, this patch takes the path of least resistance and just
overrides the default so it's the same as it was in yum. It would be
nice to have a way to access pristine build RPMs in Koji/mock, but
that's probably a much larger patch.