blog/source/_includes/flattr_payment_link.xml

<link rel="payment" href="https://flattr.com/submit/auto?url={{ url }}&amp;user_id={{ site.flattr_user | cgi_escape }}&amp;title={{ post.title | cgi_escape }}&amp;category=text{% unless post.categories == empty %}&amp;tags={{ post.categories | join: ', ' | cgi_escape }}{% endunless %}{% if post.description %}&amp;description={{ post.description | cgi_escape }}{% endif %}" type="text/html" />