docs: public static Collection<String> getKnownPGPSecureRingLocations() {
          final LinkedHashSet<String> locations = new LinkedHashSet<String>();
  
          final String os = System.getProperty("os.name");
          final boolean runOnWindows = os == null || os.toLowerCase().contains("win");
  
          if (runOnWindows) {
              // The user's roaming profile on Windows, via environment
              final String windowsRoaming = System.getenv("APPDATA");
              if (windowsRoaming != null) {
                  locations.add(joinLocalPath(windowsRoaming, "gnupg", "secring.gpg"));
              }
  
              // The user's local profile on Windows, via environment
              final String windowsLocal = System.getenv("LOCALAPPDATA");
              if (windowsLocal != null) {
                  locations.add(joinLocalPath(windowsLocal, "gnupg", "secring.gpg"));
              }
  
              // The Windows installation directory
              final String windir = System.getProperty("WINDIR");
              if (windir != null) {
                  // Local Profile on Windows 98 and ME
                  locations.add(joinLocalPath(windir, "Application Data", "gnupg", "secring.gpg"));
              }
          }
  
          final String home = System.getProperty("user.home");
  
          if (home != null && runOnWindows) {
              // These are for various flavours of Windows
              // if the environment variables above have failed
  
              // Roaming profile on Vista and later
              locations.add(joinLocalPath(home, "AppData", "Roaming", "gnupg", "secring.gpg"));
              // Local profile on Vista and later
              locations.add(joinLocalPath(home, "AppData", "Local", "gnupg", "secring.gpg"));
              // Roaming profile on 2000 and XP
              locations.add(joinLocalPath(home, "Application Data", "gnupg", "secring.gpg"));
              // Local profile on 2000 and XP
              locations.add(joinLocalPath(home, "Local Settings", "Application Data", "gnupg", "secring.gpg"));
          }
  
          // *nix, including OS X
          if (home != null) {
              locations.add(joinLocalPath(home, ".gnupg", "secring.gpg"));
          }
  
          return locations;
      }