Firefox updated when Never Check for updates selected

Can anyone explain how Firefox updated when Never Check for updates is selected?

Did you look at the "Help / About" panel? That seems to trigger the update for me.

Robin

It indeed does, that's how I force it to do so.

I looked at it but I didn't select to update it.

It auto-downloads when you look in 'about', to install whenever you next restart your browser. That you didn't select 'restart now' just meant to install later.