This is not "simple". And I'm not even talking about tracking, why is `all.js` a whooping 1 MB of JavaScript? For example, it clearly includes markdown-it but the website has zero Markdown support as far as I can tell. Spell-checking is the only non-trivial component I can imagine and even that can be plausibly replaced with a native `spellcheck` attribute.

I would instead recommend a beautifully golfed, and yet still quite readable and functional notepad app with <100 bytes of JS: https://xem.github.io/postit/