In aid of the project of Inform 7 programming, here is the the main source code for version 5 of Six. It's about 130,000 words in size. This version of the game was compiled with release 6G60 of Inform 7.
I didn't include the custom extensions, graphics or 50+ sound effects with the source, so this is not a file one can compile into the game, but 98% of the game code and everything that I think may be of most interest to other authors is in this file.
At the head of the source is the Creative Commons licence under which I released it, notes pointing out a few features of the source, and notes on navigating the source.