$ git clone -n https://src.fedoraproject.org/rpms/rubygem-pdf-core.git /var/lib/mock/f45-build-35148-693/root/chroot_tmpdir/scmroot/rubygem-pdf-core
Cloning into '/var/lib/mock/f45-build-35148-693/root/chroot_tmpdir/scmroot/rubygem-pdf-core'...
$ git fetch origin 3eeae77716e73d1d7a59e71ef1f0d04979ccd861:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-pdf-core
 * [new ref]         3eeae77716e73d1d7a59e71ef1f0d04979ccd861 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3eeae77 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild