The thing about these is that performance is often not as good as when using templates, especially when the templates are compiled to native code. Quicktemplate [1] is still the leader here IMO, and I don't think the OP project brings much that couldn't be done pretty easily with QT.
https://github.com/julvo/htmlgo
https://github.com/rohanthewiz/element
I'm sure there are many more.
The thing about these is that performance is often not as good as when using templates, especially when the templates are compiled to native code. Quicktemplate [1] is still the leader here IMO, and I don't think the OP project brings much that couldn't be done pretty easily with QT.
[1] https://github.com/valyala/quicktemplate