I tried manually typing a handful of common feed URLs relative and absolute, a firefox feed auto-finder extension, and a quick ctrl-f for feed in the source. But I guess if running an application is required for your webpages I'm better off not subscribing. That's not my kind of jam but it is understandable if your blog is for profit or it's purpose is to get you a job or something.

It doesn't need to be a modal and can (should!) fall back to a simple <a> without JS. It also didn't work even with JS for me.