code: @Nullable
      public static String getNCNameSuffix(CharSequence s) {
          if (s.length() > 1 && s.charAt(0) == '_' && s.charAt(1) == ':') {
              return null;
          }
          int localPartStartIndex = getNCNameSuffixIndex(s);
          if (localPartStartIndex > -1) {
              return s.toString().substring(localPartStartIndex);
          } else {
              return null;
          }
      }
docs: Get the longest NCName that is a suffix of a character sequence.
  
  @param s
  The character sequence.
  @return The String which is the longest suffix of the character sequence
  {@code s} that is an NCName, or {@code null} if the character
  sequence {@code s} does not have a suffix that is an NCName.