Neos\Flow\Cache\CacheManager::flushCachesByTag PHP Method

    public function flushCachesByTag($tag, $flushPersistentCaches = false)
    {
        $this->createAllCaches();
        /** @var FrontendInterface $cache */
        foreach ($this->caches as $identifier => $cache) {
            if (!$flushPersistentCaches && $this->isCachePersistent($identifier)) {
                continue;
            }
            $cache->flushByTag($tag);
        }
    }