Source

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

public function prepare_item_for_response( $block_type, $request ) {

		$fields = $this->get_fields_for_response( $request );
		$data   = array();

		if ( rest_is_field_included( 'attributes', $fields ) ) {
			$data['attributes'] = $block_type->get_attributes();
		}

		if ( rest_is_field_included( 'is_dynamic', $fields ) ) {
			$data['is_dynamic'] = $block_type->is_dynamic();
		}

		$schema       = $this->get_item_schema();
		$extra_fields = array(
			'name',
			'title',
			'description',
			'icon',
			'category',
			'keywords',
			'parent',
			'provides_context',
			'uses_context',
			'supports',
			'styles',
			'textdomain',
			'example',
			'editor_script',
			'script',
			'editor_style',
			'style',
		);
		foreach ( $extra_fields as $extra_field ) {
			if ( rest_is_field_included( $extra_field, $fields ) ) {
				if ( isset( $block_type->$extra_field ) ) {
					$field = $block_type->$extra_field;
				} elseif ( array_key_exists( 'default', $schema['properties'][ $extra_field ] ) ) {
					$field = $schema['properties'][ $extra_field ]['default'];
				} else {
					$field = '';
				}
				$data[ $extra_field ] = rest_sanitize_value_from_schema( $field, $schema['properties'][ $extra_field ] );
			}
		}

		if ( rest_is_field_included( 'styles', $fields ) ) {
			$styles         = $this->style_registry->get_registered_styles_for_block( $block_type->name );
			$styles         = array_values( $styles );
			$data['styles'] = wp_parse_args( $styles, $data['styles'] );
			$data['styles'] = array_filter( $data['styles'] );
		}

		$context = ! empty( $request['context'] ) ? $request['context'] : 'view';
		$data    = $this->add_additional_fields_to_object( $data, $request );
		$data    = $this->filter_response_by_context( $data, $context );

		$response = rest_ensure_response( $data );

		$response->add_links( $this->prepare_links( $block_type ) );

		/**
		 * Filters a block type returned from the REST API.
		 *
		 * Allows modification of the block type data right before it is returned.
		 *
		 * @since 5.5.0
		 *
		 * @param WP_REST_Response $response   The response object.
		 * @param WP_Block_Type    $block_type The original block type object.
		 * @param WP_REST_Request  $request    Request used to generate the response.
		 */
		return apply_filters( 'rest_prepare_block_type', $response, $block_type, $request );
	}