Thank you, John, but perhaps you misunderstand me. I have looked at some of those. I want to be able to look at the underlying structure of an LO rather than just the finished product. That is, to load it into Xerte 2.18 and see how the tools there relate to the finished product. I need more control over appearance and controls than seems to be available working within in the online toolkit. I could spend many hours trying to work out Xerte 2.18 on my own, but if I had an LO or two it would make that process shorter.
Andy