The plugin uses the LocalBusiness - schema.org information schema and incorporates the meta data into your websites footer using the wp_footer() hook form WordPress. The information is packed into the html code of the site and invisible to any visitor.
The part that unnerves me is the "invisible to any visitor." Wouldn't Google consider this a form of cloaking and thus shoot any SEO benefits out the door? It does put the information in the footer though which some people seem to be looking for.