Integration of browsers for feetbackd

We were talking about tangram which I like a lot for web applications and why notifications from those applications are ignoring my Librem5s sound profile setting.

Answer: tangram needs to start using feedbackd. Understood.

I thought about it and I ended up with the following question: How? Which layers of the software (webapp, browser) need to be changed how?

By notifications you mean notifications per Desktop Notifications Specification or website with an html <audio> element?