PGN chess lessons?


It is a thing. You just haven't scoured very effectively. Most of the Silman articles posted on this site, for example, offer just that, with variations to your hearts content.
Try this one:
https://www.chess.com/article/view/the-good-the-bad-and-the-ugly-1

It is a thing. You just haven't scoured very effectively. Most of the Silman articles posted on this site, for example, offer just that, with variations to your hearts content.
Try this one:
https://www.chess.com/article/view/the-good-the-bad-and-the-ugly-1

Well, if you wanted to review all the major moves in the Sicilian out to 20 moves, that could get sort of unwieldy. I don't think you'd want 384,000 game pgns (the number of Sicilians in the Chessbase online database.)
In order to have something workable, what you would have would be called a database. If you want commented games, you could get the Chess Informant, which looks provides comments on a lot of the games played by leading grandmasters.

Everyman Chess publishes their e-books in four formats: cbv, pgn, Kindle and E-pub.
They may have what you are looking for.