$ git clone -n https://src.fedoraproject.org/rpms/rust-below-model.git /var/lib/mock/f42-build-side-1-3512354-46069/root/chroot_tmpdir/scmroot/rust-below-model
Cloning into '/var/lib/mock/f42-build-side-1-3512354-46069/root/chroot_tmpdir/scmroot/rust-below-model'...
$ git fetch origin 3162f3c5b349df04fa77044183063684fd8a2d1a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-below-model
 * [new ref]         3162f3c5b349df04fa77044183063684fd8a2d1a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3162f3c Update to 0.9.0; Fixes: RHBZ#2347635