Is there SourceMaps for HTML?
Sourcemaps, ready to use for HTML today no. This is also something very complex to implement.
This can change in future. If this response was marked as correct, and someone knows after some time that my answer is not more true, please comment below I'm wrong.
It is dead simnple to generate sourcemaps in a generic way like for css, but there is no browser support for it.
Some editors have plugins to support this. But be aware: this works best for static pages. (pug/jade, ... - using this at our place with nodejs+gulp)