Ensure fonts are always loaded in the same order
We bundle fonts with Linux Tor Browser, but I recall noticing that the bundled fonts are used with different priorities on different Linux flavors, such that a given code point is displayed with Font 1 on Linux flavor A and Font 2 on Linux flavor B. This probably has to do with the order of font loading being different.
Currently we use a workaround in 000-tor-browser.js, where we enforce priorities useing the font.name* prefs. But we should investigate the underlying reason for this problem and come up with a better patch that ensures our whitelisted fonts are always applied in the same order. That way a given code point will always use the same font.