> not via a web app installation -- only assets in an ordinary filesystem directory Not sure I understand this. Every web app I build is just a set of HTML/CSS

> not via a web app installation -- only assets in an ordinary filesystem directory Not sure I understand this. Every web app I build is just a set of HTML/CSS/JS files that are served in a static fashion, which means that you could just plop that static folder onto your hard drive, click "index.html", and interact with it normally. I guess routing concerns maybe exist if you just naively hope the URL-based-routing works but it'd be easy to work around this