Enable <a href="{$a}" target="_blank">Google Fonts</a> for the font names you stipulate except for 'Default'.  When 'disabled', you have the opportunity to serve the fonts yourself through CSS / theme modification or have them already installed on the users devices.  When 'enabled' select the subset needed (latin is always included) and enter the right font weight or the font will not displayed.  <b>NOTE: Adaptable is GPLv3 licensed and may contain bugs, please verify for yourself that when disabled that Google fonts are not being used!</b>