WordPress at a glance
filter is not described

notify_post_author filter-hook . WP 4.4.0

Filters whether to send the post author new comment notification emails, overriding the site setting.

Usage

add_filter( 'notify_post_author', 'filter_function_name_8142', 10, 2 );
function filter_function_name_8142( $maybe_notify, $comment_ID ){
	// filter...

	return $maybe_notify;
}
$maybe_notify(true/false)
Whether to notify the post author about the new comment.
$comment_ID(int)
The ID of the comment for the notification.

Where the hook is called

wp_new_comment_notify_postauthor()
wp-includes/comment.php 2071
$maybe_notify = apply_filters( 'notify_post_author', $maybe_notify, $comment_ID );

Where the hook is used (in WP core)

Does not used.