NetHack 3.6.2
From the release notes: "Parchment and vellum are made from animal skin so change material composition and color for spellbooks with those descriptions from paper to leather; <i>eating those books now breaks vegetarian conduct</i>" (emphasis mine)<p>There is something heartwarming about the attention to detail in some games. NetHack, Dwarf Fortress, ... I wish more games would be made with this mindset. Many modern games seem to overemphasize the "gaming" aspect, and sometimes forget the "playing" with all its joyful intricacies.