wait, so observablehq notebook-runtime is open source? I just hit your repos on github.
So hypothetically speaking one could create an Electron app wrapper for a standalone?
I wonder if other folks fielded that idea yet or would be interested to make it work.
I’d def use an app v as a JS dataViz code snips ide 
Observable Slack bot would be my next observables shares suggestion to assist dataViz geeks sharing good data munging code snips. too soon?
it’s really easy to make an electron app, yes; just follow https://beta.observablehq.com/@jashkenas/downloading-and-embedding-notebooks
or http://visionscarto.net/observable-jekyll/
If you’re ok with it calling external resources on the web then it’s just a matter of putting that exported code on index.html . In other words the most difficult part is making sure all your dependencies are available locally, if you want the app to be self contained.