I think you've missed the point of what they were asking... which is probably if there are tools to facilitate authoring and publishing in plain text.
The year is 2020, developers demand decent tooling for authoring and publishing plaintext.
Pretty sure anyone working in plaintext is using something better than ed or similar. emacs, vim, and many others are plaintext editors. It's not hard to imagine we can come up with even better tools for it as well.
I suspect the best of those tools will be called Emacs and vim for some more decades.