WordPress at a glance
filter is not described

comment_feed_orderby filter-hook . WP 2.8.0

Filters the ORDER BY clause of the comments feed query before sending.

Usage

add_filter( 'comment_feed_orderby', 'filter_function_name_9363', 10, 2 );
function filter_function_name_9363( $corderby, $this ){
	// filter...

	return $corderby;
}
$corderby(string)
The ORDER BY clause of the query.
$this(WP_Query)
The WP_Query instance (passed by reference).

Where the hook is called

WP_Query::get_posts()
wp-includes/class-wp-query.php 2456
$corderby = apply_filters_ref_array( 'comment_feed_orderby', array( 'comment_date_gmt DESC', &$this ) );
wp-includes/class-wp-query.php 2865
$corderby = apply_filters_ref_array( 'comment_feed_orderby', array( 'comment_date_gmt DESC', &$this ) );

Where the hook is used (in WP core)

Does not used.