the option to open a private tab as a normal tab is GONE. This is how I use Firefox: someone sends me a link, I click on it and it opens in a private tab by default. If I need to sign in to see it (e.g. private Instagram links) then I open it in a normal tab. This option is now simply gone.
I'm going to wager this is such a hyper-niche use case that the devs might genuinely not be aware of anybody doing this at all. Reminds me of the relevant XKCD, basically.
It's already acknowledged by the devs though, the feature should still/again be there soon, but it stays a nightly-only feature for the time being.