code: @Nonnull
    @ReturnsMutableCopy
    public ICommonsOrderedSet <String> getAllMimeTypeStringsForExtension (@Nonnull final String sExtension)
    {
      ValueEnforcer.notNull (sExtension, "Extension");
  
      final ICommonsOrderedSet <String> ret = new CommonsLinkedHashSet <> ();
      final ICommonsList <MimeTypeInfo> aInfos = getAllInfosOfExtension (sExtension);
      if (aInfos != null)
        for (final MimeTypeInfo aInfo : aInfos)
          ret.addAll (aInfo.getAllMimeTypeStrings ());
      return ret;
    }
docs: Get all mime types that are associated to the specified filename extension.
  
  @param sExtension
  The filename extension to search. May not be <code>null</code>.
  @return Never <code>null</code> but maybe empty set if no mime type is
  associated with the passed extension.