I don't know when it appeared, but navigating to about:profiles shows - Create a New Profile - a list of the existing profiles - - for each one of those, a "

I don't know when it appeared, but navigating to about:profiles shows - Create a New Profile - a list of the existing profiles - - for each one of those, a "Launch profile in a New Browser" button for any one that isn't already running along with "Rename" and "Remove" buttons, so that feels about as full-featured a management screen as one could ask for. The only(?) user-hostile behavior is having to know that about: URL