wp-includes/fonts/class-wp-font-collection.php:220Sanitizes and validates the font collection data.
$dataarray$required_propertiesarrayoptionalarray()array|WP_Error private function sanitize_and_validate_data( $data, $required_properties = array() ) { $schema = self::get_sanitization_schema(); $data = WP_Font_Utils::sanitize_from_schema( $data, $schema ); foreach ( $required_properties as $property ) { if ( empty( $data[ $property ] ) ) { $message = sprintf( // translators: 1: Font collection slug, 2: Missing property name, e.g. "font_families". __( 'Font collection "%1$s" has missing or empty property: "%2$s".' ), $this->slug, $property ); _doing_it_wrong( __METHOD__, $message, '6.5.0' ); return new WP_Error( 'font_collection_missing_property', $message ); } } return $data; }Introduced in 6.5.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/fonts/class-wp-font-collection.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.