ApiGen\Parser\Reflection\ReflectionClass::getIndirectSubClasses PHP Method

    public function getIndirectSubClasses()
    {
        $subClasses = [];
        foreach ($this->getParsedClasses() as $class) {
            if ($class->isDocumented() && $this->getName() !== $class->getParentClassName() && $class->isSubclassOf($this->getName())) {
                $subClasses[] = $class;
            }
        }
        uksort($subClasses, 'strcasecmp');
        return $subClasses;
    }