wp_list_bookmarks provides no way to retrieve category id

I’m using the function documented at http://codex.wordpress.org/Function_Reference/wp_list_bookmarks

This function provides ‘%id’ as a way to output the link category, but it prepends the phrase “linkcat-” to it. It does not provide the category in a useful way to link to subcategories. It seems that the only way to display a specific category is to name it explicitly.

Is there any way to retrieve the link category id so I can reuse it in a link to drill down to the specific link category??

if( $_GET['cat_id'] ) {
    $args = array(
        category => $_GET['cat_id'],
        category_before => '<h2><a href="?page_id=' . $post->ID . '&cat_id=%id">',
        category_after => '</a></h2>',
    );
    wp_list_bookmarks( $args );
}
else {
    $args = array(
        category_before => '<h2><a href="?page_id=' . $post->ID . '&cat_id=' . $cat->term_id . '">',
        category_after => '</a></h2>',
    );
    wp_list_bookmarks( $args );
}

In http://core.trac.wordpress.org/browser/tags/3.2.1/wp-includes/bookmark-template.php it shows the following lines:

$defaults = array(
 ...
 'category_before' => '<li id="%id" class="%class">',
 ...
 )
 $output .= str_replace(array('%id', '%class'), array("linkcat-$cat->term_id", $class), $category_before);

This seems like a bug to me, since you are encoding a css class into a value. Wouldn’t this be more general usage like so:

$defaults = array(
 ...
 'category_before' => '<li id="linkcat-%id" class="%class">',
 ...
 )
 $output .= str_replace(array('%id', '%class'), array($cat->term_id, $class), $category_before);