This page tests what DESIGN.md section 8 needs from Dropbox (experiments E1, E2 and E14). It talks only to Dropbox. Tokens stay in this tab and are never shown; the log below shows no token and no key.
From your app's Settings tab in Dropbox's Developer Console. The app needs the App folder access type, the scopes files.metadata.read, files.content.read and files.content.write, and this page's address listed as a redirect address:
The file tests write one file, tv-tracker-test.csv, in the app's own folder and leave it there. On a second device, List the folder shows what the first one wrote, without writing anything (E2).
An add upload when the file exists; an upload of the same content at the current rev; then the file is deleted, its revisions listed, and it is written again.
Takes a minute or two. It checks that the revision listing, which gives at most 100 at a time, reaches every one.
Between the two steps, change the file outside this page: on dropbox.com open the app's folder under Apps and upload another file named tv-tracker-test.csv over it.