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filter is not described

wp_nav_menu_args filter-hook . WP 3.0.0

Filters the arguments used to display a navigation menu.

Usage

add_filter( 'wp_nav_menu_args', 'filter_function_name_3016' );
function filter_function_name_3016( $args ){
	// filter...

	return $args;
}
$args(array)
Array of wp_nav_menu() arguments.

Where the hook is called

wp_nav_menu()
wp_nav_menu_args
wp-includes/nav-menu-template.php 71
$args = apply_filters( 'wp_nav_menu_args', $args );

Where the hook is used (in WP core)

wp-includes/class-wp-customize-nav-menus.php 1178
 	add_filter( 'wp_nav_menu_args', array( $this, 'filter_wp_nav_menu_args' ), 1000 );