The official client is closed source and releases are obfuscated, but there have been mappings (MCP) for quite a few years now. http://minecraft.gamepedia.com/

The official client is closed source and releases are obfuscated, but there have been mappings (MCP) for quite a few years now. http://minecraft.gamepedia.com/Programs_and_editors/Mod_Coder_Pack http://minecraft.gamepedia.com/Programs_and_editors/Mod_Code... The protocol is also well documented: http://wiki.vg/Protocol http://wiki.vg/Protocol