* <li>os.version: The operating system version</li>
 * </ul>
 * <p>
 * Supported OS families include:
 * <ul>
 * <li>windows: All Windows variants</li>
 * <li>win9x: Windows 95, 98, ME, CE</li>
 * <li>winnt: Windows NT variants</li>
 * <li>unix: Unix-like systems (including Linux)</li>
 * <li>mac: macOS (including Darwin)</li>
 * <li>os/2: OS/2 variants</li>
 * <li>netware: Novell NetWare</li>
 * <li>dos: DOS variants</li>

     */
    private static final String FAMILY_WIN9X = "win9x";

    /**
     * OS family that can be tested for. {@value}
     */
    public static final String FAMILY_NT = "winnt";

    /**
     * OS family that can be tested for. {@value}
     */
    private static final String FAMILY_OS2 = "os/2";

    /**
     * OS family that can be tested for. {@value}
     */