e.g. https://test.wikipedia.org/wiki/Draft:Foobar
The page curation toolbar is shown on the right (if not, click on "Curate this article" under "Tools" in the left-side navigation).
Only two buttons are available -- "Minimize" (works fine) and "Go to the next page in the queue". The latter goes to a page in the mainspace, not in the draftspace. For now, we should hide the toolbar entirely in the draftspace. In the future we might look into making the toolbar correctly navigate through the draft feed.