The goal of these config snippets is to be able to include them - not to be examples to copy, paste and edit =). Can you rewrite this please so that the only thing that's not a comment are the suggested headers? I.e. this kind of thing should be possible:

    //sites-available/wide-open.com
    server {
        ...

        include h5bp/cross-domain-ajax-insecure.conf;
    }

OR:
    
    //sites-available/restricted.com
    server {
        ...

        if ($http_origin ~* (https?://.*\.yoursite\.com(:[0-9]+)?)) {
                include h5bp/cross-domain-ajax-insecure.conf;
    }
    
Whereas this can't be configured, so doesn't use a snippet at all:

    //sites-available/restricted.com
    server {
        ...

        add_header 'Access-Control-Allow-Origin' "http://yoursite.com";
    }