> Firefox added profile switching recently.

I think this was as recent as 25 years ago?

Recently they added some new UI. There was and still is (I think) classic Profile Manager UI, which you can launch with

  ./firefox -ProfileManager

or access UI in about:profiles.

But you don't have to use any of those anyway - see my comment above (a response to parent).

Odd - they've had that for years, but only on the command line. Wonder if it's different under the hood? They also have firefox containers which also never quite became a first-class feature (you have to install a plugin).

>Works good.

does it? same binary, same machine, same display, same 781 other heuristics.