I haven't tried to import the export file onto my new-used, fast laptop, but it does the session display in a readable--and *editable*-- format well enough. And even the exported text file could be edited if word wrap is off. Though i can't think of why changes wouldn't be easier in the ff interface.
The import looks a little confusing, esp weird is the 'Switch to Export,' which seems to only occasionally, quickly shows the Export pane. But it's a clean export/import, so I won't transfer any tagging or such by any other add-ons I tried, didn't like and removed, esp the container ones (though having 2 separate containers with 2 separate logins to the same site would be handy). This has a clean, simple interface and those extra sessions I worried about, they're the auto-backups i turned om, though the max is 10. Hopefully this add-on is too hands-off to interfere with any other tab mgr add-ons I run. But this is almost certainly the add-on I want to transfer my 300+ tabs on 14 windows to my new system (I may look at some others). Thanks, mate.

Cool raw export. An option without favicon should be awsome (:

I've just tried "REPLACE existing session" feature - it looks like it just closes the current session and nothing else. "ADD ..." feature works properly. By the way where are the autobackup files located in FS?