WordPress at a glance
function is not described

WP_Post_Type::add_supports() WP 4.6.0

Sets the features support for the post type.

This is a method of the class: WP_Post_Type

No Hooks.

Return

Null. Nothing.

Usage

$WP_Post_Type = new WP_Post_Type();
$var = $WP_Post_Type->add_supports();

Changelog

Since 4.6.0 Introduced.

Code of WP Post Type::add supports: wp-includes/class-wp-post-type.php WP 5.2.2

<?php
public function add_supports() {
	if ( ! empty( $this->supports ) ) {
		add_post_type_support( $this->name, $this->supports );
		unset( $this->supports );
	} elseif ( false !== $this->supports ) {
		// Add default features.
		add_post_type_support( $this->name, array( 'title', 'editor' ) );
	}
}