[calebm]

I've been calling these Single-File Web Apps. I've written a couple myself:

≈ https://fuzzygraph.com ≈ https://hypervault.github.io/

[calebm]

Slight correction: I'd only refer to it as a "Single-File Web App" if it has no external dependencies (where as the "HTML Tool" definition allows for external dependencies loaded from CDNs).

[cxr]

I wouldn't call either of these tools that either. Using View Source reveals that there's a pretty obvious build step and confronts you with massive minified blobs. There's no way a person is going to be able open that HTML as a "single file" in their text editor to pick up development where it was left off. (In that regard, the HTML tools in the linked post are closer to the definition, even when they're written to load a module from a CDN.)