$ git clone -n https://src.fedoraproject.org/rpms/rubygem-metaclass.git /var/lib/mock/f45-build-35028-693/root/chroot_tmpdir/scmroot/rubygem-metaclass
Cloning into '/var/lib/mock/f45-build-35028-693/root/chroot_tmpdir/scmroot/rubygem-metaclass'...
$ git fetch origin 14feca2e2aa8fc47430bcd57eff6075dc8a7869d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-metaclass
 * [new ref]         14feca2e2aa8fc47430bcd57eff6075dc8a7869d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 14feca2 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild