Latest Chromium 53 user agents:

User Agent Platform Device
Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/53.0.2785.143 Chrome/53.0.2785.143 Safari/537.36 Ubuntu Unknown
Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML like Gecko) Ubuntu Chromium/53.0.2785.143 Chrome/53.0.2785.143 Safari/537.36 Ubuntu Unknown
Mozilla/5.0 (X11; Linux i686) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/53.0.2785.143 Chrome/53.0.2785.143 Safari/537.36 Ubuntu Unknown