$ git clone -n https://src.fedoraproject.org/rpms/rust-gix-ref.git /var/lib/mock/f40-build-2248533-53954/root/chroot_tmpdir/scmroot/rust-gix-ref
Cloning into '/var/lib/mock/f40-build-2248533-53954/root/chroot_tmpdir/scmroot/rust-gix-ref'...
$ git fetch origin 7a3b30b4c513c560363d2d05a86b258446686b4a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-gix-ref
 * [new ref]         7a3b30b4c513c560363d2d05a86b258446686b4a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 7a3b30b Update to version 0.38.0