wp-includes/class-wp-customize-widgets.php:200Inspects the incoming customized data for any widget settings, and dynamically adds them up-front so widgets will be initialized properly.
public function register_settings() { $widget_setting_ids = array(); $incoming_setting_ids = array_keys( $this->manager->unsanitized_post_values() ); foreach ( $incoming_setting_ids as $setting_id ) { if ( ! is_null( $this->get_setting_type( $setting_id ) ) ) { $widget_setting_ids[] = $setting_id; } } if ( $this->manager->doing_ajax( 'update-widget' ) && isset( $_REQUEST['widget-id'] ) ) { $widget_setting_ids[] = $this->get_setting_id( wp_unslash( $_REQUEST['widget-id'] ) ); } $settings = $this->manager->add_dynamic_settings( array_unique( $widget_setting_ids ) ); if ( $this->manager->settings_previewed() ) { foreach ( $settings as $setting ) { $setting->preview(); } } }Introduced in 4.2.0. 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.