I'd keep very quiet about that if I were you.

The problem with having free time is that inevitably, the universe finds a way for you to fill it.

Or worse. Your boss finds a way to fill it.

Or worse still. Your friends find a way to fill it.

Or - quite possibly the worst - someone reminds you about one of your many charitable (on your case, free software) causes. And finds you work there.

If I were you, I'd just delete this comment, and not mention it ever again. It's the only way to ensure enjoyment of your well-deserved free time. :-)