docs: public static AppDescriptor of(String appName, String packageName, Version appVersion) {
          String[] packages = packageName.split(S.COMMON_SEP);
          String effectPackageName = packageName;
          if (packages.length > 0) {
              effectPackageName = packages[0];
          }
          E.illegalArgumentIf(!JavaNames.isPackageOrClassName(effectPackageName),
                  "valid package name expected. found: " + effectPackageName);
          return new AppDescriptor(ensureAppName(appName, effectPackageName, $.requireNotNull(appVersion)),
                  packageName,
                  appVersion);
      }