$ git clone -n https://src.fedoraproject.org/rpms/rubygem-excon.git /var/lib/mock/f45-build-34885-692/root/chroot_tmpdir/scmroot/rubygem-excon
Cloning into '/var/lib/mock/f45-build-34885-692/root/chroot_tmpdir/scmroot/rubygem-excon'...
$ git fetch origin aa654b87f66e7c0df1e5dea4aae05e5830fecbe0:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-excon
 * [new ref]         aa654b87f66e7c0df1e5dea4aae05e5830fecbe0 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at aa654b8 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild