Would love if the "table of contents" (upper panel) could be displayed as a dropdown list instead of a flat listbox -- it occupies a sizeable chunk of vertical real estate as-is. Otherwise, it's fine, just no replacement for the old "Notes by Firefox".

I like this app. It's simple. Visually it's somewhat drab. If it could have some colour or be able to have skins attached it might work like a happy face.

Needs more work. It does not have an icon so you will find it in the Sidebars button. The bottom box is for typing in notes, I guess, but
the entries in the top box show up and interfere with the bottom box.
I guess that is so you can edit the top box entries. It's a bit of a mess.
I was looking for something like the old Quick Notes.