$ git clone -n https://src.fedoraproject.org/rpms/rust-dav1d-sys.git /var/lib/mock/f42-build-side-1-3585964-46912/root/chroot_tmpdir/scmroot/rust-dav1d-sys
Cloning into '/var/lib/mock/f42-build-side-1-3585964-46912/root/chroot_tmpdir/scmroot/rust-dav1d-sys'...
$ git fetch origin 71f1ba84884e0d5d93ef924ea0a357cd87575645:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-dav1d-sys
 * [new ref]         71f1ba84884e0d5d93ef924ea0a357cd87575645 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 71f1ba8 Update to version 0.8.3; Fixes RHBZ#2368882