Tally Lamp for the S1H

A japanese reader sent me this:

Hello, site owners.
It is introduced on the following site that the function that the Tally lamp can be externally attached is hidden in S1H.
https://sumizoon.hatenablog.com/entry/2020/05/25/235338
Panasonic officials also said that this function is only installed in the S1H at exhibitions etc.
Probably it was prepared by a third-party manufacturer to make an external tally lamp in the future.
The actual operation image is also published below.

Thanks!