The Webhook Plugin for the Twilio CLI is a tool designed to test and develop Twilio webhooks without requiring public exposure, manual configuration, or triggering webhook events. The plugin can emulate Twilio webhook requests and send them to a local or public URL of choice, allowing users to validate their webhooks with benefits such as no need to configure the webhook URL in Twilio or manually trigger the webhook event. Users can test secured and unsecured webhooks by passing in the Auth Token and using various command-line arguments to override default parameters. The plugin is an open-source project on GitHub, and its developer provides additional resources and support for users looking to improve their productivity with Twilio.