wp-includes/class-wp-customize-manager.php:3308Filters heartbeat settings for the Customizer.
$settingsarrayarray public function add_customize_screen_to_heartbeat_settings( $settings ) { global $pagenow; if ( 'customize.php' === $pagenow ) { $settings['screenId'] = 'customize'; } return $settings; }Introduced in 4.9.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/class-wp-customize-manager.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.