Firefox has an undocumented about:config preference "font.system.whitelist" to specify a list of which fonts are exposed to web content (such as the default set

Firefox has an undocumented about:config preference "font.system.whitelist" to specify a list of which fonts are exposed to web content (such as the default set shipped with your OS). The preference is used by the Tor browser. https://bugzilla.mozilla.org/show_bug.cgi?id=1121643 https://bugzilla.mozilla.org/show_bug.cgi?id=1121643