We are happy to answer your questions about the code or discuss technical ideas.

Please complete the following checklist (by adding [x]):

• I have searched open and closed issues for duplicates
• This isn't a feature request
• This is not a report about my app not working as expected

I'm using https://kojipkgs.fedoraproject.org//packages/firefox/127.0/1.fc40/x86_64/firefox-127.0-1.fc40.x86_64.rpm (from https://koji.fedoraproject.org/koji/rpminfo?rpmID=38850613) with browser.display.use_document_fonts set as 1 in about:config, which means that font preferences are respected. I'm forced to use this because browser.display.use_document_fonts.icon_font_allowlist:

Material Icons, Material Icons Extended, Material Icons Outlined, Material Icons Round, Material Icons Sharp, Material Icons Two Tone, Google Material Icons, Material Symbols Outlined, Material Symbols Round, Material Symbols Rounded, Material Symbols Sharp

...isn't comprehensive enough, even for iconography at https://www.google.com/search. Consequently, please do not override the browser font. There's no reason to. I have font.name.sans-serif.x-western set to monospace, so ProtonMail appears very out-of-place.