@rauschma Not a niche if you think about how jupyter notebooks are essentially executable code in a file that mixes markdown and code. If you start writing a lot of code in code blocks in markdown, pretty soon you need the entire tool chain to support it (formatters, linters, run-as-script, import library from code block, test running, etc).
Anyhow at least 3 projects in python doing this: https://github.com/matthewdeanmartin/markmodule?tab=readme-ov-file#markdown-is-a-hammer-everything-is-a-nail