$ git clone -n https://src.fedoraproject.org/rpms/rubygem-vcr.git /var/lib/mock/f45-build-35400-695/root/chroot_tmpdir/scmroot/rubygem-vcr
Cloning into '/var/lib/mock/f45-build-35400-695/root/chroot_tmpdir/scmroot/rubygem-vcr'...
$ git fetch origin 53dedec4382434ebae090a460e0cc2a7edb330b2:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-vcr
 * [new ref]         53dedec4382434ebae090a460e0cc2a7edb330b2 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 53dedec Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild