err... WHAT ORGANISATION???  My computer is a stand-alone "home" computer which I own and manage, and is not networked to anything, not even a printer.  When I connect to the internet it is by password protected mobile hotspot through my phone, but I make this connection only when I need it and disconnect when it is not in use. 

Hi! I have been using Firefox browser for so long I can't remember when I first started using it, so "June 2004" was an absolute guess to satisfy the too-inflexible parameters of the login process. However, to the problem... Firefox has been my default browser for the past few centuries and is likely to remain so until the internet itself becomes obsolete. Recently I also installed Brave because I want to separate some of my internet activities from the rest. The Brave installation process apparently set Brave as my default browser without consulting me. So I went into my Firefox settings to return Firefox to "default" status. That was simple enough, but what I also noticed at the top of my Settings page is a message I've never seen before which reads, "Your browser is being managed by your organisation." err... WHAT ORGANISATION??? My computer is a stand-alone "home" computer which I own and manage, and is not networked to anything, not even a printer. When I connect to the internet it is by password protected mobile hotspot through my phone, but I make this connection only when I need it and disconnect when it is not in use. So, this unexpected message alarms me. Have I been hacked and my browser been taken over by some unknown entity of whose existence I was unaware until I saw this message... or what? How do I block whoever/whatever the "organisation" is and take back permanent, secure control of my browser? Anyone who can throw some light on this will be much appreciated. Thank you.