WordPress translation

OMFG that is the most stupid code I saw in core for some time.
Don’t follow the comments there, if you want to use a different flavor of open sans just write a plugin that deregister the style and add the one you want to be used instead

function replace_open_sans() {
  wp_deregister_style('open-sans');
  wp_register_style('open-sans', 'http://fonts.googleapis.com/css?family=Open+Sans:300');
  wp_enqueue_style('open-sans');
}
add_action( 'wp_enqueue_styles', 'replace_open_sans' );

code taken from http://www.webdevelopmentgroup.com/2014/01/replace-open-sans-in-wordpress-3-8/