$ git clone -n https://src.fedoraproject.org/rpms/rust-thread-tree.git /var/lib/mock/f45-build-45497-823/root/chroot_tmpdir/scmroot/rust-thread-tree
Cloning into '/var/lib/mock/f45-build-45497-823/root/chroot_tmpdir/scmroot/rust-thread-tree'...
$ git fetch origin 6efa27a9dd4d59b40e7a46ed433d0cdd3d2011f5:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-thread-tree
 * [new ref]         6efa27a9dd4d59b40e7a46ed433d0cdd3d2011f5 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6efa27a Regenerate with rust2rpm v28