$ git clone -n https://src.fedoraproject.org/rpms/rust-postmark.git /var/lib/mock/f45-build-43934-809/root/chroot_tmpdir/scmroot/rust-postmark
Cloning into '/var/lib/mock/f45-build-43934-809/root/chroot_tmpdir/scmroot/rust-postmark'...
$ git fetch origin a23c51d9807ed0fea349d58b7bac66b68f5577f9:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-postmark
 * [new ref]         a23c51d9807ed0fea349d58b7bac66b68f5577f9 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a23c51d Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild