„MetaNote intends to be the most versatile editor imaginable. Right
click on features in the editor and edit the code behind them. Don’t
like the way ‚Find‘ works? — right click on it, and edit the code.
Need a new button in the toolbar? So add it already, with a single
click. Share packs of extensions and macros with other users.
Everything in MetaNote is under your control, effortlessly, at runtime.“

The project is still in its alpha stages, but a really unique approach. The developer is looking for people that like to jump in and help out making it as versatile as possible.

More about it here