$ git clone -n https://src.fedoraproject.org/rpms/rust-test-generator.git /var/lib/mock/f41-build-side-1-3134942-39764/root/chroot_tmpdir/scmroot/rust-test-generator
Cloning into '/var/lib/mock/f41-build-side-1-3134942-39764/root/chroot_tmpdir/scmroot/rust-test-generator'...
$ git fetch origin 76f86fc99412b006e27ac0ca3ea5cbf244ec975f:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-test-generator
 * [new ref]         76f86fc99412b006e27ac0ca3ea5cbf244ec975f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 76f86fc no longer needed