BTW, in the spirit of being helpful: if you're using private windows just for 'fresh session' behavior, Firefox offers two other knobs for that outcome: Profiles and Containers. In Chrome I'm with you that Incognito can be a very cheap way to login to a site multiple times, but in FF you have more choices about that problem
I’m logging in and out of client accounts - often for services that don’t do delegate access - so private windows work nice for me to make sure that I’m always cleared out of what I was working on before changing to a different project. Often I copy things in private windows that aren’t secrets, it just happens to be how I used the feature.
Containers and Profile are great - but - I’m not trying to have 50+ of them at work, much easier to flip open a private window.
I acknowledge my usecase is unusual and for most I think the feature makes sense - I just want to be able to turn it off, an about:config would be fine.
Actually, sorry, it seems to be https://addons.mozilla.org/en-US/firefox/addon/temporary-con... and https://github.com/GodKratos/temporary-containers) based solely on the language present in the add-on and commit history