Yep, like Hyperclay. https://news.ycombinator.com/item?id=49690814

They're like lightweight versions of https://github.com/kem-a/AppManager which is for AppImages.

Not a bad thing, but it's just another dependency and tied to an OS-specific base software install.

They could work well pre-installed on the Mecha Comet with a bunch of app files ready to launch.

Can the added layers guarantee a new level of security or privacy like zero telemetry or keyjacking? Protection from bad actors is a good thing while making things faster and easier overall. Browser extensions are a security risk, right?

Java applets were a good idea in the sense that so long as you had Java installed, the applet was just sitting there on a webpage. Finding and managing the apps is the problem, and using browser bookmarks is a decent solution to it. The web page should demo the app, and there can be an 'install local' button next to it. But at some point all these local versions need to be updated and then not be messed with like browser extensions can be. FanFare would be a decent name.