No, it's compiled into the output.

At the moment, the best way to do this would be to customise the theme for the authoring tool. How you go about this depends on whether you always want your theme to have the home button or just sometimes.

I'm afraid I don't do much themeing nor do I use the authoring tool day-to-day - but there's plenty of discussion about this here on the forum (this for example) and of course you can always pop into the authoring tool chat room if you have any questions.