Board Thread:Support Requests - Getting Technical/@comment-24655611-20200930104822/@comment-1038387-20201001051947

The classic source editor doesn't exist on UCP.

For about a week after launch, you could access the window by turning off all editors in prefs, but that was an unintended oversight. However, that edit screen wasn't the Legacy one, it was closer to what WP and Gamepedia have.