Edna is a fork of Heynote with a bunch of changes.

Mostly it supports multiple notes and it's a web app, not a desktop app.

I could build a desktop app but it would not offer almost any advantages given that Edna can also save notes on disk (that's how I use it).

You can use Chrome's "Install" feature to make it look act like a native app (it opens in it's own window and acts independently of the browser).