$ git clone -n https://src.fedoraproject.org/rpms/rust-uu_cksum.git /var/lib/mock/f40-build-1971896-25224/root/chroot_tmpdir/scmroot/rust-uu_cksum
Cloning into '/var/lib/mock/f40-build-1971896-25224/root/chroot_tmpdir/scmroot/rust-uu_cksum'...
$ git fetch origin eff89bde8bde3f455198ce00765dcffc816a4a77:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-uu_cksum
 * [new ref]         eff89bde8bde3f455198ce00765dcffc816a4a77 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at eff89bd Update to version 0.0.27; Fixes: RHBZ#2260200