Opening mhtml files with Firefox

At times I get saved webpages by people using the mhtml format (Google Chrome uses that format) to look into.
While it is a plaintext format with added binaries, it would be much work for just one single such file to extract the html data. I did so in the past, but it would be easier to just have a Chrome installed as well, but I don`t like having Chrome, I would be more happy when FFx is the only browser I need.

I tried looking for an mhtml supporting AddOn on https://addons.mozilla.org but that resulted in 215 results, and the whole first page of results seems to not have one AddOn that would support mhtml.

I hope it is okay to ask for a certain kind of AddOn on here, but I did not see a more appropriate sub-forum to ask in.

I have not heard of any extensions to read MHTML files in Firefox 57+.

Considering the number of interested users, I can only assume that it’s difficult to implement using the WebExtensions APIs.