When I copied FF 85.0.2 to another computer, it lost its settings AND its add-ons. I had to do them all over again.
Assuming it was keeping them in Windows 7, I searched C: for Firefox. I got these on the source computer but they could be from past Portable Firefoxes:
The target computer isn't available right now.
Of course everything is supposed to stay in the Portable Firefox folder, so it's pretty serious.
Did you start FirefoxPortable.exe directly or via the PA.c Platform? If so, Firefox runs in portable mode. If you run firefox.exe directly (which will happen if you pin it to the taskbar without the platform or set it as your default) it runs in local mode, just like an installed app.
Sometimes, the impossible can become possible, if you're awesome!
I started it by:
Firefox.exe is deeper in the folders