About this Add-on
Still not possible to implement using WebExtensions without changes from Firefox side.
Adds private tabs.
Usage: see screenshots.
Also you can create private bookmarks to always open some links in private tabs: just prefix “private:” before URL, example: private:https://addons.mozilla.org/
In English: http://forums.mozillazine.org/viewtopic.php?t=2665169
In Russian: http://forum.mozilla-russia.org/viewtopic.php?id=58122
Source code and issues tracker: https://github.com/Infocatcher/Private_Tab
Please read about known issues before reporting bugs:
Some styles for userChrome.css/Stylish to change private tabs appearance:
Works only in Gecko 20.0 and higher (Firefox 20.0+ and SeaMonkey 2.17+) because used API doesn't exist in older versions!
See https://bugzilla.mozilla.org/show_bug.cgi?id=800193 for information about “Warning: Only internal code is allowed to set the usePrivateBrowsing attribute” in the Error Console.
[*] Toggle private state using tab duplication: try restore text in URL bar (#237).
[x] Fixed private protocol in Firefox 37-43 (caused by `nsIIOService.newChannelFromURIWithLoadInfo(…, null)` failure) (#247).
[*] Updated Indonesian (id) locale, thanks to Muhammad Anwari Ramadhan.
[x] Fixed ability to open new private tab in Firefox 54+ (with browser.newtab.preload = true) (#252).
[+] Added privateTab.replaceTabAndTogglePrivate() API.
[x] Fixed ability to open private:… URI in already opened tab (will be used workaround with tab duplication) (#251).