Re: @Paul Crawford
Well, for what it's worth I've gone to the trouble of adding my votes to both the Ubuntu and upstream bug trackers.
> and it is symptomatic of an organisation that, because it is not on their patch, don't care.
Personally I think Mozilla are a well-meaning org taking on a number of good projects and overall doing a pretty good job while of course having more on their plate than they can do and having to prioritise.
Yes, it looks like they're continuing to fail on this but it is if I'm not mistaken a Linux only issue, it relates to printing which I think large numbers of users do not do from the browser beyond a boarding card PDF. I've never even noticed this myself (ok, mainly because I rarely print), so perhaps that's why it's not as much of a biggy for the vast majority of users and Mozilla as it is for you and some others.
Shouldn't adding this to user.js work, even across version updates since it's in the profile?
// Change default paper size from US-Letter to A4: