docs: private void addCustomAttributesToSSOToken() {
          SingleSignonToken ssoToken = getSSOToken(subject);
          if (ssoToken != null) {
              if (customRealm != null) {
                  if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled()) {
                      Tr.debug(tc, "Add custom realm into SSOToken");
                  }
                  ssoToken.addAttribute(AttributeNameConstants.WSCREDENTIAL_REALM, customRealm);
              }
              if (authProvider != null && !authProvider.endsWith("Form")) {
                  ssoToken.addAttribute(AuthenticationConstants.INTERNAL_AUTH_PROVIDER, authProvider);
              }
          }
      }