$ git clone -n https://src.fedoraproject.org/rpms/grass-compiler.git /var/lib/mock/f45-build-12997-444/root/chroot_tmpdir/scmroot/grass-compiler
Cloning into '/var/lib/mock/f45-build-12997-444/root/chroot_tmpdir/scmroot/grass-compiler'...
$ git fetch origin 137dab450cd2f9197223945bde314be88b5d0850:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/grass-compiler
 * [new ref]         137dab450cd2f9197223945bde314be88b5d0850 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 137dab4 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild