> I assume it content-extracts that on upload?

Hister always stores the original material.

> That way you could also switch from an extracted view to a "full" view in the UI.

It isn't even needed, we just need a SingleFile specific extractor (an interface in Hister to parse specific page content and provide custom previews) that provides the full original HTML for the preview panel.

> Hopefully I'll find time to contribute!

I'd appreciate it. <3