While you are logged in, you personally can access the Debug View of any Pen. It allows you to see the authored code without an iframe or any other CodePen influence. That makes it nice for testing things exactly as they would be out in the wild, wild internet.
The URL format for Pens in Debug View is:
Debug View is a little bit dangerous for us though. By not using a sandboxed iframe or any other protections AND not showing any CodePen UI, it opens a door for abuse. That's why we required at least you to be authenticated to see it. (If you weren't authenticated, you just get redirected to Full Page View).
But another pretty good way to know a Pen isn't abuse-y is if it's owned by a PRO member. So now we've opened that up. If you're a PRO member, you can view Pens you own on any browser in Debug View without logging in. Just go to the URL and it works just as expected.
We still send the Live View URL to your phone through the SMS feature, just because that's probably generally a little bit more useful as PRO member, but of course you can just edit the URL once it's on your phone to hop over to Debug View easily.