What causes webfonts to not display on my FX profile?
For some reason, under my FX profile, webfont specimens on sites like http://www.fonts.com/font/itc/itc-franklin-gothic?QueryFontType=Web#product_top or http://www.linotype.com/1129914/ClassicGrotesque-family.html fail to display, and instead show my default Firefox font. Starting Firefox in Safe Mode doesn't solve the problem, nor does changing my default Firefox fonts back to "serif" and "sans-serif", etc. Running Firefox with a new profile does solve the problem though. What causes this problem? I don't want to start with a new profile and lose all my bookmarks, addons, settings, etc.
Alla svar (4)
Is downloadable fonts enabled?
You can check the gfx.downloadable_fonts.enabled pref(s) on the about:config page.
You can also try to reset all preferences by (temporarily) renaming or moving the prefs.js file to see if that helps.
Downloadable fonts is enabled— didn't fix. I tried resetting the preferences, it worked! Now how do I find out which preference is specifically causing the problem?
You can try to sort by user set on the about:config page (click the status header) to make it easier to spot modified prefs and start with looking at font related prefs to see if anything springs out.
Found the problem— It was that the "send referrer header" was turned off.