Plumbers do anything with pipes, and electricians do anything with wire. We do not have the ability to read your mind to figure out what you do not know, or how your brain is wired ;D.

Gas lines have always been obviously a plumber's job to me. So is everything an electrician does. Maybe if you have some specific tasks you are wondering about, I could clear those up?

Not every plumber does everything that plumbers do, and not every electrician does everything that electricians do. My plumber doesn't do gas or RPZA testing as he gets enough business without. Many electricians don't assemble communications cables.

JM$.02W

I get the impression a lot of non-power-carrying wire (cable, phone, data, etc.) is done by non-electricians since it's not high voltage.

Depending on where you are, it may not be regulated or it may be regulated as a separate specialty (then don't get me started on the union aspects of this. Spent a long time fighting that battle back in my younger days).