It's nice that people care about RSS and add tools for it!
Btw if you want to improve the feed finding, here's an article that lists a bunch of ways for finding them even if they're not linked in the html metadata.
Thanks for sharing, I'll check it out! Lighthouse seems to go much further in extracting the feeds and even finds some likely variants by brute force or crawls for links.
For this browser extension I aim to have a small but curated list of ad-hoc derives instead of one-fits-all solution. This makes me wonder: if RSS is supported by a website but is not accessible at all, perhaps the right approach would be to simply ask the owners to provide access to it.
That all depends on how much time you have. Also, WordPress and other software create RSS feeds by default, so many people don't even know their website has a feed.