Although it's not possible to access {{ content_for_footer }} directly, as this Liquid tag dynamically generates HTML and JavaScript necessary for NationBuilder to properly render a particular page, it's possible to use Liquid filters to replace, remove, or append content. For example, the following filter will replace the call for the en_US version of the Facebook script with a German version in content_for_footer:

{{ content_for_footer | replace: 'connect.facebook.net/en_US', 'connect.facebook.net/de_DE' }}