content_type_urls
Return the available content representations and URLs for a resource.
The result is a list of {ContentType, Url} pairs derived from the resource's
content-type dispatch rules. This can be used to present links to HTML, JSON,
or other export formats.
For example:
{% for content_type, url in id|content_type_urls %}
<a href="{{ url }}">{{ content_type|content_type_label }}</a>
{% endfor %}