The HTML file save by Save Page WE contains all of the resources required by the web page, including the images, fonts, style sheets and scripts. This is exactly the same information that is saved in an MHT or MAFF file.

However, the big difference is that the file saved by Save Page WE can be opened in any browser without any add-ons being required, and is therefore furure-proof.

Whereas, an MHT or MAFF file can only be opened in Firefox using an add-on such as UnMHT or MAF, both of which are legacy add-ons that do not work with multi-process (e10s) Firefox.