A) .maff support has been discontinued, in Sept 5th 2018 (which is still some time off). On http://maf.mozdev.org/ it says "A guided procedure can be used to convert your saved pages to a different file format. By default, the procedure will look for MAFF and MHTML archives and convert them to HTML pages which can be opened with any browser." B) the maff add-on ( here is not a single (old) version of the extension https://addons.mozilla.org/en-US/firefox/addon/mozilla-archive-format/ working with this ), which is supposed to provide a conversion utility (UNTIL Sept) for ESR-Firefoxes ("This add-on is only compatible with Firefox Extended Support Release (ESR) until September 5, 2018.") does not provide a single compatible version on the download page. C) having upgraded to 60.1.0esr (64-bit) from the openSuse Repo I finally thought it was to time to convert those files; just HOW? D) workarounds for Linux do not exist, as opposed for Apple (https://langui.net/maff-viewer/) or Windows (https://github.com/idaviddesmet/MaffViewer) So what should I do? (Please spare me "use a zip utility to view") -- We are talking 62000 files, which after extraction into Html will expand into 10 times that many at least. Alas I do need the data. (I see at least two broken promises in the help pages provide. Never mind total abolition of a widely used function, thank you for the inconvenience.)