Source

File: wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php

public function __construct( $post_type ) {
		$this->post_type = $post_type;
		$this->namespace = 'wp/v2';
		$obj             = get_post_type_object( $post_type );
		$this->rest_base = ! empty( $obj->rest_base ) ? $obj->rest_base : $obj->name;

		$this->meta = new WP_REST_Post_Meta_Fields( $this->post_type );
	}