wp-includes/class-wp-customize-widgets.php:1361Determine if a widget is rendered on the page.
$widget_idstringbool public function is_widget_rendered( $widget_id ) { return ! empty( $this->rendered_widgets[ $widget_id ] ); }Introduced in 4.0.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/class-wp-customize-widgets.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.