It appears that (at least) Safari cannot open mhtml files. The benefit of a tool such as what the OP shared is that it can produce plain html pages that are ope

It appears that (at least) Safari cannot open mhtml files. The benefit of a tool such as what the OP shared is that it can produce plain html pages that are openable by anyone. (also, I tried mhtml in Chrome using the proper flag and it doesn't appear to store/inline/render static assets correctly).