$ git clone -n https://src.fedoraproject.org/rpms/rust-silver.git /var/lib/mock/f41-build-861565-169832/root/chroot_tmpdir/scmroot/rust-silver
Cloning into '/var/lib/mock/f41-build-861565-169832/root/chroot_tmpdir/scmroot/rust-silver'...
$ git fetch origin 4fc2d2a9b7bb8754399dab9c8ce8b401f804b229:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-silver
 * [new ref]         4fc2d2a9b7bb8754399dab9c8ce8b401f804b229 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4fc2d2a Bump git2 dependency from 0.18 to 0.19