$ git clone -n https://src.fedoraproject.org/rpms/R-pillar.git /var/lib/mock/f39-build-1524660-36035/root/chroot_tmpdir/scmroot/R-pillar
Cloning into '/var/lib/mock/f39-build-1524660-36035/root/chroot_tmpdir/scmroot/R-pillar'...
$ git fetch origin 157841acd1220fd6661a49c04f91a726ee4d7989:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-pillar
 * [new ref]         157841acd1220fd6661a49c04f91a726ee4d7989 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 157841a Rebuilt for https://fedoraproject.org/wiki/Fedora_39_Mass_Rebuild