The biggest value I got from JustHTML here was the API design.
I think that represents the bulk of the human work that went into JustHTML - it's really nice, and lifting that directly is the thing that let me build my library almost hands-off and end up with a good result.
Without that I would have had to think a whole lot more about what I was doing here!
Do you mind elaborating? By API design, do you mean how they structured their classes, methods, etc. or something else?