$ git clone -n https://src.fedoraproject.org/rpms/R-RUnit.git /var/lib/mock/f45-build-5909-345/root/chroot_tmpdir/scmroot/R-RUnit
Cloning into '/var/lib/mock/f45-build-5909-345/root/chroot_tmpdir/scmroot/R-RUnit'...
$ git fetch origin 5f28ab64962e977cc0eacbec4c5c7f24ce98b391:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-RUnit
 * [new ref]         5f28ab64962e977cc0eacbec4c5c7f24ce98b391 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5f28ab6 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild