What can the retail brokers see from my MT4 EA.

I know if my EA places TP and SL orders the can see these on there dealing desk

Can the read the following also
- EA MQ4 code
- Global variables
- Live or demo accounts, can they see on both, if they can at all ?
- Can the see the indicator ex4 files as well ?

In order...

No
I think yes, but verify for yourself.
They could care less about demos, although i think they'll "support" them. But don't call the trading desks asking for a demo quote.
No.

The only thing they can see is the order placed with the SL and TP and eventually the TS if it is set up by the EA and not handled by the EA.

It can also see the magic number. They cannot see the indicator on your chart nor in your folder etc...

That's all

and also they can see order comment. So sometimes they may know exactly what you are running (if you dont change comment)

Q: I understand that they know an order is from an EA, are they able to see the name given to that EA ?

So they can see magic number and comments, thats makes sense.

In my order comments = "DONT STEAL FROM ME !!"