wp-includes/class-wp-customize-manager.php:2252Removes the signature in case we experience a case where the Customizer was not properly executed.
$callbackcallable|nulloptionalnullcallable|null public function remove_preview_signature( $callback = null ) { _deprecated_function( __METHOD__, '4.7.0' ); return $callback; }Introduced in 3.4.0. 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.