I unfortunately do not have a running list. The one that made me drop Firefox last time was the mermaid.js docs site. None of the sidebar navigation was clickable but only on Firefox, the same issue did not appear on Safari or Chrome. It appears they have since fixed that issue as I retested and it appears fine.

The "give me examples" is sort of a moving target, anecdotally I have run into many more completely or partially broken sites when using Firefox as compared to Chrome and Safari. It is likely that some or all of those examples are now fixed but the pain in the moment is enough to keep me from using the browser long term.

Is it this site? https://mermaid.js.org/intro/

It works fine for me.

Often people forgot they have installed an obscure exstension in Firefox and that is breaking the site, trying another browser it works, concluding that Firefox must be the problem, while it was the extension. That is also why people usually cannot reproduce the problem later or give concrete examples.

Concrete examples:

The web interfaces for both Jitsi and Zoom fail to recognise my web camera. I've gone through the permissions settings a dozen times and Firefox says that it sees camera, but it only displays a black feed. Vivaldi correctly accesses the camera on both sites.

imascientist.org.uk makes it "impossible" to sign up for outreach sessions under Firefox. The div with the sessions has a `max-width` parameter, but the contents are significantly larger than this width, resulting in the buttons being outside the rendering area and inaccessible. I have to go into the dev tools and edit the CSS every time I open the page.

These are just the issues that I've dealt with today. Don't get me wrong - I'm literally typing this in Firefox at this moment. However, it doesn't help anyone to pretend that these issues never pop up. I simply feel that the benefits outweight these annoyances.

I just tested both sites from my default firefox profile.

zoom worked without problem.. both audio and video..

imascientist.org.uk i opened the registration page and it showed without problem buttons where in the end of the page as i would expect.

It look like it is something in your end and not with firefox..

Very strange. I run Zoom constantly in FF - my company does several events a week that I edit, so i’m thick in the weeds on zoom’s site doing admin/recording management stuff. Almost 3 years on zoom’s site almost every single day, never had to swap browsers. Mac Studio if that matters.

Never had problems with Zoom and Jitsi in Firefox. Should work fine. I don't think the problem is because Firefox renders sites differently.

On imascientist.org.uk I don't see a sign up button, only login.

If I record correctly, Mozilla has said that like 97% of all problems people has is with problems is due to extensions, not Firefox. '

When you have a site not working as expected, start Firefox in "Troubleshoot Mode" (alt-key then in the menu at the top Help > Troubleshot mode) that starts Firefox with addons turn off. If the site works, restart and turn of addons one by one to you see which one creates the problem.