Latest Headless Chrome 77 user agents:

User Agent PlatformDevice
Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML; like Gecko) HeadlessChrome/77.0.3865.120 GNU/LinuxUnknown
Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) HeadlessChrome/77.0.3865.120 Safari/537.36 GNU/LinuxUnknown
Mozilla/5.0 (Windows NT 6.3; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) HeadlessChrome/77.0.3835.0 Safari/537.36 Windows 8Unknown
Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) HeadlessChrome/77.0.3844.0 Safari/537.36 Windows 10Unknown
Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) HeadlessChrome/77.0.3835.0 Safari/537.36 Windows 10Unknown
Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) HeadlessChrome/77.0.3854.0 Safari/537.36 GNU/LinuxUnknown
Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) HeadlessChrome/77.0.3835.0 Safari/537.36 GNU/LinuxUnknown
Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) HeadlessChrome/77.0.3844.0 Safari/537.36 GNU/LinuxUnknown