Oh wow, you found a use for it! That's wonderful! :) I'm thinking of updating my notebook to make use of Observable's viewof API, which would break the current usage. I will post a comment here with a warning when I do so. Or do you think I should instead write a new notebook with a distinct URL to keep things working, like "@jobleonard/ace-viewof"?

Hmm. Either way, I guess. Perhaps I can import the old version of your notebook. Thank you!