How to make Firefox open all links in a private window by default? (I mean, unless I manually chose to open a link in "normal" mode, or it's a link from a site to itself, it should open it in a private window).
It's annoying when I accidentally open some unknown and/or garbage website in "normal" mode and have to clean up all the crap it has left in cookies, cache, etc… But it's important to keep data of some sites between relaunches, so, for example, I won't have to log in to StackOverflow every time.
Using some hidden settings and/or extensions to solve this problem is OK.
I've found a similar question, but its accepted answer is not good enough for me, as it requires setting up whitelist for cookies, and it's not clear what will happen with other kinds of data that websites can leave.