What does the red badge with a number on the dock icon signi

I keep seeing a little red badge with a number on the DTPO icon, similar to the badge that appears on the Mail.app icon. I can’t figure out what it signifies. There are no unread items in my inboxes.

It’s the number of recently captured items, e.g. via Take Plain/Rich Note services.

How do I get it to go away? Is there a preference or setting I can change so it doesn’t appear?

No. But it’s reset after deactivating DEVONthink.