I was positively surprised recently when the new Firefox profile manager (about:profilemanager) was introduced. https://www.tech2geek.net/how-to-use-the-new-updated-profile-manager-in-firefox-2025/ is an article about that. However, I thought it's just a new visual UI with an in-browser switcher for the existing profiles (that I already had setup). However, it does not appear so. The differences I see: ### old profile management * was managed by `about:profiles` or when starting FIrefox with `-P` * is saved in `~/firefox` and the `profiles.ini` clearly and quite obviously mentions them there, so it's easy to manage them. I also found this old support article: https://support.mozilla.org/en-US/kb/profile-manager-create-remove-switch-firefox-profiles ### new profile management * automatically asks on startup if more than one profile exists * is managed by `about:profilemanager` or with the Firefox burger menu * seems to be saved in `~/.mozilla/firefox/Profile Groups` (Linux path here) in some .sqlite files, and I do not quite understand the format. Not mentioned in `profiles.ini`. * also, when you change something here (even like opening a profile?), you cannot open `about:profiles` anymore, because it says "Some Firefox process has made changes to your profile, […] you need to restart Firefox", only after a restart further changes would be possible, which I find quite confusing but it also indicates somehow the features belong together? And this seems to be the new one: https://support.mozilla.org/en-US/kb/profile-management#w_whats-the-difference-between-profiles-and-multi-account-containers ## Questions * What are the differences here (I may have missed)? * How can the new profile feature save so few files? Is it technically called "profile groups"? * And the most important: How can I migrate an old profile? (In order to use the new features and GUI etc. I quite like)