The best way I can recommend is to look for the fix to show up in Safari release notes. Beta release notes can give you the earliest indication of what release of Safari the fix will be included in, though it's not a guarantee.

Requesting a lab appointment is available to members of the Apple Developer Program — if you're already a member, this is one of the best perks of your subscription!

Looks like you got your wish: developer.apple.com/documentatio...

Got it. I'll share it with the team.

Can you be more specific about the kind of interest would you like to be able to signal?

You are correct that WebKit Bugzilla bugs are, for the most part, public (security bugs are not). Feedback Assistant reports are also a good way of reporting sensitive information to Apple directly, such as when you need to include a sysdiagnose, for example.

The most basic way to think about it is that any web content (e.g. web page rendering, JavaScript execution) are a WebKit Bugzilla report. Feedback Assistant reports are the right place for browser issues (e.g. user-interface and browser features like Reader, bookmarks, tabs, profiles, etc.)

Improvements are ongoing, as Bugzilla is a deeply tentacled application, but I'm pleased we were able to bring this to the WebKit and broader web community.