FreePBX PJSIP Registered Extensions
If you use a Asterisk-based PBX system such as FreePBX with a web GUI and make use of PJSIP as your default channel driver, this method is a quick and dirty method of displaying your currently-registered endpoints in a browser tab. The output will display your registered contacts, the private IP of the endpoint (useful for troubleshooting), the User Agent of the device, and the expiration time of the registration. While all of this data is exposed via the CLI, it's not always visible in the GUI, or you might have non-cli-nerds that need access to this information. When you are turning up a PBX this can be a handy tool for your remote hands person to see exactly what devices are online and which are not, right from a phone browser.