Over in the Drupal project, we're using a variant of phpdoc/doxygen, and it looks pretty similar to what is described here.

One thing that we do that I don't see here is that if a file doc block is used, we put @file at the top of it, but I don't see @file in the list of tags here. Is it considered unnecessary?

Another thing we have, from Doxygen, is the ability to define "groups" with @defgroup, and then to add Structural Elements to these groups with @ingroup. We then make a Topic page for each group, and it shows the "group" documentation and a list of all the Structural Elements that were added to the group. Would that be possible to add to this standard? Or is there a defined way for individual projects to extend the standard?

Finally, a @code tag (also from Doxygen) is useful for adding code within documentation. I guess you've indicated that within DocBlocks you should use Markdown, but to me, using @tags seems more consistent. I mean, you have @link, rather than using a Markdown syntax for links... why not also @code?