LiChess Tools by Siderite is a powerful extension designed for Firefox users that significantly enhances the functionality of the popular chess platform, lichess.org. This subscription-based tool introduces a range of features aimed at improving the learning and playing experience. Key functionalities include extended interactive lessons that allow users to explore all variations of a position, practice against specific opponents, and access local computer analysis even when offline. Additionally, it supports enhanced PGN imports, enabling users to merge multiple game files into a single study, facilitating better analysis and repertoire building.

The extension also provides numerous user-friendly features such as sound notifications for friends' games, customizable menus, and various tools for analyzing and studying chess games. Users can draw on the board, manage their friends list, and enjoy a variety of context menus to streamline their analysis. With support for mobile devices and a plethora of options for customization, LiChess Tools is an essential asset for chess enthusiasts looking to deepen their engagement with the game.