savePrivateTabsInSessions doesn't work
See #82. Now Firefox itself don't save private tabs. So, now all filtrations are hardcoded inside built-in sessions mechanism.
Also there is AMO policies that prohibit such things: https://blog.mozilla.org/addons/2010/02/23/private-browsing-support-required-for-add-ons/
OK. I wish there could be an extension to not save history for certain tabs (or only save history of a page when wanted to) yet still kept in sessions, as Private Tab has been able to work previously. This function would be useful, and I would not need Private Browsing.
Yes, I understand. And that's why there was savePrivateTabsInSessions preference (for debug purposes, but not only).
But for now it's very difficult to alter built-in things (hard to do it correct and very hard to make something robust).