Resolving conflicts in CBL via the rest api

What does this mean??

{ _id: 'c105d6dee5139889df38a0d8580ba626',
  _conflicts: [ '6-31331f58af4371a386dbf5c0d0b05b9b' ],
  _rev: '6-31331f58af4371a386dbf5c0d0b05b9b',
  ...

The server version is also at 6-31331f58af4371a386dbf5c0d0b05b9b. What is the conflict?