I am not familiar with this part of the code, but generally, the answer to this question is « lack of manpower, but if you volunteer to implement it, we'll be glad to help you out and have you onboard. »
If anybody motivated to help us implement features reads these lines, the next step is to join us on IRC: irc.mozilla.org, channel #introduction .
I moved that bug to a place where someone who might know something about the matter might actually see it...
Re:Firefox Developer Edition
by harmonicon on Monday November 10, 2014 @11:36AM
(#8584509)
I have to say I rather like it that way but I guess I am not the target user group for such accessibility features.
There is an open bug but no love: [ https://bugzilla.mozilla.org/show_bug.cgi?id=790706 ]. Firefox forces high-contrast colors, completely destroying HTML rendering, with no option to disable this behavior.
Using a high contrast theme in Windows doesn't mean i don't want to see web pages as their developer intended.
Chrome gets it right, why can't Firefox?