https://fingswotidun.com/images/notanos_4.png
It was predominantly designed to be as dumb a server as possible and do everything client side. It implemented a basic file IO interface so you can write files and get directory listings.
Anything fancy client side could be leveraged by the ability to execute commands on the server and providing a local named socket for commands to connect to to establish a websocket connection to the client. The core server then plays no further part and it's up to the executed command to send a message to open a window and provide the html/js for the content which will handle all future websocket messages for that window. Essentially all windowed apps with a complex server side component are free to implement their own protocol.
That simple architecture allowed me to construct some nice interactions https://fingswotidun.com/images/notanos_drag_drop.gif
I didn't think it could be a commercial product though. I appreciate that being a 'Product' might afford one the resources to develop such a thing more fully, but then it is just another thing to buy.
I fundamentally believe that things like this have to be free and open source to be viable long term. Otherwise you just have an impressive dead-end like GeoWorks was, back in the day.