It was there because of a mistake.

channels.template is already added by channels.sub

As received orientation from from E3 team.

Substitution file is used in module build to set channel names, since that shouldn't change
too much with time and particular detector.

VMM and Hybrid numbers are left to be changed in the st.cmd file since that can change more often.

Before this, you would need to put array of values into ST-S.
Now you can simply put 1 or 0 into AllST-S and it will set all channels.

OOPT "on change" field is needed because for some reason without it even
if you put PINI=NO in all these three ST-S records, it processes on IOC
initialization, which I don't think is desired.