wp-includes/class-wp-block-parser.php:311Returns a new block object for freeform HTML
$inner_htmlstringWP_Block_Parser_Block public function freeform( $inner_html ) { return new WP_Block_Parser_Block( null, array(), array(), $inner_html, array( $inner_html ) ); }Introduced in 3.9.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/class-wp-block-parser.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.