"Sync via Dropbox" extra?

On macOS I just saw a notification that a new “extra” was available called “Sync via Dropbox”, but I can’t see it anywhere in the “extras” window.

What is it?

Has anything changed in the Dropbox sync setup?

New items should be marked as unread (bold) in Sidebar > Extras. But this tip isn’t new actually, might have been due to a network hiccup. Which version of DEVONthink 3 do you use?

Yes I was aware of the “bold for new” thing, but I don’t see it.

Network hiccup. OK.

I’m using version 3.8.7.

What is it?

This is an update to the Help > Tutorials > Sync with Dropbox tutorial.

Has anything changed in the Dropbox sync setup?

Minor details, like where to disconnect a connected app in Dropbox, but the essentials are the same. It has just been updated for DEVONthink 3.