$ git clone -n https://src.fedoraproject.org/rpms/rust-fern.git /var/lib/mock/f45-build-41604-784/root/chroot_tmpdir/scmroot/rust-fern
Cloning into '/var/lib/mock/f45-build-41604-784/root/chroot_tmpdir/scmroot/rust-fern'...
$ git fetch origin 7c3a1ed0c1c2b59b20f3c84184f44bc0a4d62e4c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-fern
 * [new ref]         7c3a1ed0c1c2b59b20f3c84184f44bc0a4d62e4c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 7c3a1ed Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild