> Mozilla's own site expounds on "Don't Break the Web" as

I'm a former Mozillian. I don't give a shit how it has been retconned by whomever happened to be writing copy that day, if indeed they have—it isn't even worth bothering to check.

"Don't break the Web" means exactly what it sounds like it means. Anything else is a lie.

> If the machine is so complex that nobody wants to maintain it, it will go unmaintained

There isn't a shortage of people willing to work on Web browsers. What there is is a finite amount of resources (in the form of compensation to engineers), and a set of people holding engineering positions at browser companies who, by those engineers' own admission, do not satisfy the conditions of being both personally qualified and equipped to do the necessary work here. But instead of stepping down from their role and freeing up resources to be better allocated to those who are equipped and willing, they're keeping their feet planted for the simple selfish reason that doing otherwise might entail a salary reduction and/or diminished power and influence. So they sacrifice the Web.

Fuck them.

Sounds like you're volunteering to maintain the XSLT support in Firefox. That's great! That means when Chrome tries to decommission it, users who rely upon it will flock to Firefox instead because it's the only browser that works right with the websites they use.

Firefox ascendancy is overdue. Best of luck!