Doxygen hook_nodeapi() documentation

I'm getting some log errors after upgrading 4.7beta to 4.7.0. In looking through the core modules to see where the errors are occuring, I saw in taxonomy_nodeapi() a case for 'rss item'. However, the API documentation for hook_nodeapi does not list this as a possible value of the $op parameter. Is this an omission in the documentation, a deprecated $op value, or what?

http://api.drupal.org/api/HEAD/function/hook_nodeapi

using grep pulls up the following instances of this case being used in my installed modules:

modules/comment.module:309: case 'rss item':
modules/event/event.module:689: $extra = node_invoke_nodeapi($node, 'rss item');
modules/event/event.module:1942: case 'rss item':
modules/node.module:1450: $extra = node_invoke_nodeapi($item, 'rss item');
modules/taxonomy.module:1187: case 'rss item':
modules/upload.module:400: case 'rss item':