From the introduction: The Sundered Epoch: d20 RPG System, or SE:20, is a role-playing game designed for the “action hero” style of fiction. It is a universal system and can be used in any timeline or setting. Publisher's blurb: The SRD is provided as a free document. While it includes all the basic rules needed to play the game, it is the raw, basic rules with minimal detail and information. The default setting is designed for a modern setting, but can easily be adapted to a medieval setting. User summary: Despite being designated as a "System Source Reference Document", The Core Rules SRD provide the core rules of the game without any re-use option or license option. Additionally, "SRD" use is restricted by copyright which exclusively prohibits anything except "personal use".