The device operating system.

| Enums ||
|---|---|
| `DEVICE_SYSTEM_UNSPECIFIED` | No operating system specified. |
| `SYSTEM_OTHER` | Other operating system. |
| `SYSTEM_ANDROID` | Android operating system. |
| `SYSTEM_IOS` | Apple iOS operating system. |
| `SYSTEM_CROS` | ChromeOS operating system. |
| `SYSTEM_WINDOWS` | Microsoft Windows operating system. |
| `SYSTEM_MAC` | Apple macOS operating system. |
| `SYSTEM_LINUX` | Linux operating system. |