It launches a private exchange where you act as an escrow. Users can connect to you and place offers to buy or sell bitcoin. If there is no dispute, they hit a button that causes your node to automatically release the bitcoin to the btc buyer. If there is a dispute, you can talk to both users via encrypted messages to figure out what happened and release the btc to the aggrieved party.
Currently 4 people are running public coordinators and you can try it yourself here [note that you need a tor-compatible browser like Brave]:
http://robodexarjwtfryec556cjdz3dfa7u47saek6lkftnkgshvgg2kcumqd.onion/
You can also watch a demo here: