wp-includes/html-api/class-wp-html-processor.php:6320Inserts an HTML element on the stack of open elements.
$tokenWP_HTML_Token private function insert_html_element( WP_HTML_Token $token ): void { $this->state->stack_of_open_elements->push( $token ); }Introduced in 6.4.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/html-api/class-wp-html-processor.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.