I would like Firefox to open any link that comes from another application (IRC, Discord, Steam, games, etc.) in a Private window. The current behavior is to create a new tab in my current main session, which could lead to privacy issues.
I don't want a plugin for this; I want it to be default behavior, or at least one that can be enabled in about:config (separate from browser.privatebrowsing.autostart).
(This behavior also pairs well with the multiple suggestions asking for each private window having its own profile/context, e.g https://connect.mozilla.org/t5/ideas/allow-for-multiple-parallel-private-browsing-sessions/idi-p/176....)