Form_Settings_Page::register_rest_api_settings()

	public function register_rest_api_settings() {
		$this->add_page_content();

		foreach ( $this->tabs as $id => $tab_args ) {
			$setting_args = array(
				'type'         => 'object',
				'description'  => $tab_args['rest_description'],
				'show_in_rest' => array(
					'schema' => array(
						'type'       => 'object',
						'properties' => array(),
					),
				),
				'default'      => array(),
			);

			foreach ( $tab_args['field_manager']->get_fields() as $field ) {
				if ( ! isset( $this->sections[ $field->section ] ) ) {
					continue;
				}

				if ( ! isset( $this->subtabs[ $this->sections[ $field->section ]['subtab'] ] ) ) {
					continue;
				}

				$setting_args['show_in_rest']['schema']['properties'][ $field->id ] = $this->build_rest_schema_for_field( $field );
				$setting_args['default'][ $field->id ]                              = $this->get_rest_default_for_field( $field );
			}

			if ( empty( $setting_args['show_in_rest']['schema']['properties'] ) ) {
				$setting_args['show_in_rest'] = false;
			}

			register_setting( $id, $id, $setting_args );
			add_filter( "sanitize_option_{$id}", array( $this, 'validate' ), 10, 2 );
		}
	}