That's the problem, I can't figure out what type of file it is. The file is just called Mac. I appreciate your response though. I know Mac OS isn't popular, and wasn't expecting an answer. Hopeful, the browser version will be saveable at some point because I'm really enjoying your game!
Unfortunately the browser version won't ever have the save feature. The save button gives you a string of characters that you can paste in later to save your game, but Unity's Web version doesn't allow copy / pasting to outside text files. I'm not sure why :/