Here is a summary of the text: ngrok has introduced a new local traffic routing feature that allows developers to route calls from their ngrok servers to local phone numbers. The author, Kyle Kelly-Yahner, demonstrates how to use this feature by setting up four Twilio phone numbers in different regions (US, EU, AP, and Australia) and playing music from local artists through ngrok's local data centers. To set up each number, the author uses ngrok's routing feature to forward calls to a specific port on their server, where they play a song stored in a "Jams" directory. The author then configures Twilio to route incoming calls to this port, playing the corresponding song for callers. This hack enables developers to test apps with reduced latency and adds a touch of fun with music-themed voice requests.