PGN is a standard file format used to store and exchange chess games. It allows for the notation of moves, along with additional information such as player names, event details, and game results. The PGN format has become the de facto standard for chess game notation, enabling easy sharing and analysis of games across different platforms.

By mid-2023, Chessable’s library had expanded to include world-class repertoires from the likes of Fabiano Caruana and Anish Giri. The "15th July" snapshot represents a peak moment for community-driven PGNs—files that allow users to take their favorite courses into analysis engines like ChessBase or private Lichess studies for deeper engine-aided exploration. Breaking Down the "T Top" Collection