wp-includes/blocks/heading.php:24Adds a wp-block-heading class to the heading block content.
$attributesarray$contentstringstringfunction block_core_heading_render( $attributes, $content ) { if ( ! $content ) { return $content; } $p = new WP_HTML_Tag_Processor( $content ); $header_tags = array( 'H1', 'H2', 'H3', 'H4', 'H5', 'H6' ); while ( $p->next_tag() ) { if ( in_array( $p->get_tag(), $header_tags, true ) ) { $p->add_class( 'wp-block-heading' ); break; } } return $p->get_updated_html();}Introduced in 6.2.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/blocks/heading.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.