You can think of this as part of the documentation, though it isn't in the same namespace.
This is the test start page
To create a new test page, replace “start” in the URL bar at the top with the kind of topic name you can imagine,
all lowercase, with underscores, not spaces. Then enjoy seeing what appears when you click on the “Create this page” button (the pencil-plus: 
).
Save if you like. But if you save, when you're done, delete the whole page simply by removing all the content and saving.