How, as a programmer, to report bugs I find in core Gecko browser-engine behavior in Firefox

Question

When I’m programming a Web app and I run into a problem that only seems to happen in one browser, I know that a somewhat-essential step among my overall programming tasks as

Answer 1

https://bugzilla.mozilla.org/enter_bug.cgi?product=Core&format=default is the URL you want.

That’s because in the case of Firefox, the right bugzilla “product” to use for browser-engine (Gecko) bugs is actually Core (not the Firefox component—and there is no Gecko component).

That URL above takes you directly to an actual bug-reporting page—that is, as you’d want, it completely skips all the designed-for-first-time-bug-reporters step-by-step guided-help stuff.

You do need to then manually choose the right “component” from the Component list there, but if you already know the right component, you can make a bookmark that includes it; e.g., https://bugzilla.mozilla.org/enter_bug.cgi?product=Core&component=DOM%3A%20Workers&format=default is a URL that will let you report problems with Firefox Web-Workers behavior.

Adding the &format=__default__ parameter/value is the important part needed to get bugzilla to skip all the designed-for-first-time-bug-reporters step-by-step guided-help stuff.