gistfile1.php

<?php

class MrT extends Plugin 
{
	public function action_atom_get_collection( $xml, $params, $handler_vars )
	{
		 if ( Controller::get_action() == 'tag_collection' ) {
		 	$xml->title = _t( 'Posts Tagged %s', array( htmlentities(Controller::get_var('tag')) ), 'MrT' );
		 }
	}
}