Running Phoenix with XR support requires SSL/HTTPS to be enabled. There is a script to run the Phoenix application with SSL.
Just navigate to packages/phoenix-ng
in the terminal and use this command:
yarn start:ssl
Now navigate to https://localhost:4200
(notice the https) in your browser and you should have SSL enabled.
NOTE: You may see a "Security Risk" warning that you will need to accept.
Check out the WebXR API Emulator extension to test and debug XR directly in the browser.