I distro hopped and it somehow kept all my Firefox data + my command prompt profile.

Today I removed Linux Mint and installed Ubuntu 22.04 LTS, and when fully installed, I opened Firefox and it literally opened all the tabs I had left open when I shut down Mint. It also kept my browser extensions and all my login data. I can type "y" and it shows youtube, and all my school stuff (microsoft office) is all logged in as well. I opened the command prompt and it kept my green on black theme, which is not by default. What the hell happened here? Like, coincidentally, I don't mind, I wasn't exactly looking forward to setting everything up again, but this really shouldn't happen, should it?