Rated 5 out of 5 stars

per Firefox user 96c98f el oct. 23, 2017 · enllaç permanent

The loss of this plugin is a game changer. I like many others have a vast library of MHT files.
The reason: you can save a page with active links. This MHT file is then content searchable within Windows via the standard Windows Search.

The answer ( of sorts ) i've found so far, Save Page WE, (not as capable). As for the reader, well there is a plugin for Chrome, EML, MHT viewer with Drive, which mostly works.
Word of course will read MHT ( after a fashion if it was saved with Mozilla Archive Format, and IE ( depreciated and gradually being replaced by Edge). Edge cannot by default read MHT. There is a plugin, but it is near useless.

A great loss.