$ git clone -n https://src.fedoraproject.org/rpms/rust-ron.git /var/lib/mock/f40-build-1897497-25065/root/chroot_tmpdir/scmroot/rust-ron
Cloning into '/var/lib/mock/f40-build-1897497-25065/root/chroot_tmpdir/scmroot/rust-ron'...
$ git fetch origin 7abbd4ebf68f6ca154e08aea3fd8e0b1dfa1c19e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-ron
 * [new ref]         7abbd4ebf68f6ca154e08aea3fd8e0b1dfa1c19e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 7abbd4e Update to version 0.8.1; Fixes RHBZ#2232491