$ git clone -n https://src.fedoraproject.org/rpms/rust-dav1d-sys.git /var/lib/mock/f42-build-side-1-3498697-45963/root/chroot_tmpdir/scmroot/rust-dav1d-sys
Cloning into '/var/lib/mock/f42-build-side-1-3498697-45963/root/chroot_tmpdir/scmroot/rust-dav1d-sys'...
$ git fetch origin baa2986573e848511a9c0a431599cd89a6693d63:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-dav1d-sys
 * [new ref]         baa2986573e848511a9c0a431599cd89a6693d63 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at baa2986 Bump system-deps build-dependency from 6.2 to 7