$ git clone -n https://src.fedoraproject.org/rpms/rust-primes.git /var/lib/mock/f45-build-44003-809/root/chroot_tmpdir/scmroot/rust-primes
Cloning into '/var/lib/mock/f45-build-44003-809/root/chroot_tmpdir/scmroot/rust-primes'...
$ git fetch origin c744e69483a3a8e397e7dd1a3e33eb96f1d3b6e3:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-primes
 * [new ref]         c744e69483a3a8e397e7dd1a3e33eb96f1d3b6e3 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c744e69 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild