No, it isn't. And no, there are none.
What's more relevant for normal typing is to look at my Sym mod. As you can clearly see from the Programmer Colemak site, the underscore-hyphen and quote-doublequote keys are used heavily in coding. But they're also used much in normal typing!
Look at the BigBag ergo page for more info, under the Sym mod.
( Θώθ) ～( See "DreymaR's Big Bag Of Keyboard Tricks" )
So Programmer Colemak is so unknown that there are no websites to learn it.
How do I learn it then?
How am I supposed to answer that? If you're set to learn it, contact its creator. Or, you know, do what most people do and just learn it. With your mind, you know.
I don't think very many people use that particular AltGr layer. I'd much much rather use my own, of course. And so would most people who made such a layer.