wp-includes/class-wp-duotone.php:932Registers the style and colors block attributes for block types that support it.
$block_typeWP_Block_Type public static function register_duotone_support( $block_type ) { /* * Previous `color.__experimentalDuotone` support flag is migrated * to `filter.duotone` via `block_type_metadata_settings` filter. */ if ( block_has_support( $block_type, array( 'filter', 'duotone' ), null ) ) { if ( ! $block_type->attributes ) { $block_type->attributes = array(); } if ( ! array_key_exists( 'style', $block_type->attributes ) ) { $block_type->attributes['style'] = array( 'type' => 'object', ); } } }Introduced in 6.3.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/class-wp-duotone.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.