This is a very simple mod as a proof of concept. All it does is that, whenever your health (i.e the health of player 1, so it's not particularly useful in multiplayer) changes, it outputs that value to the file script-output/health.txt.

The point of this is that an external utility of some variety could monitor that file, and use that to configure an out-of-band display (for example, a giant LED health bar, or a RGB keyboard).

As for if it's a good idea for your hard drive to to rewrite a file at 60 fps... probably not. Currently it doesn't rewrite the file if the data is the same; in future the output rate could be limited to a lower value easily enough.