Menu callback; regular HTML page with OpenID 1.0 <link> element.
function openid_test_html_openid1() {
drupal_add_html_head_link(array(
'rel' => 'openid.server',
'href' => url('openid-test/endpoint', array(
'absolute' => TRUE,
)),
));
drupal_add_html_head_link(array(
'rel' => 'openid.delegate',
'href' => 'http://example.com/html-openid1',
));
return t('This page includes a <link rel=...> element containing the URL of an OpenID Provider Endpoint.');
}