Firefox generally updates in the background, not downloading a full new browser but only the required components. You can however go to Options>Advanced>Update then check either never update or the option to download the updates then allow you to choose whether to install them.

You may want to never click (Never Update) because updates fix bugs and security issues, not just add new features.

Updates are not done by way of say a .exe file as the fake updates try to do.

As Firefox is also for Mac OSX and Linux besides Windows, they are a software update in Firefox with full or partial .mar file depending on if you missed a update.

example: http://download.cdn.mozilla.net/pub/mozilla.org/firefox/releases/28.0/update/win32/en-US/

To clarify -

I want to see the downloaded file after I have downloaded it, whether the DL is auto or initiated by me, I want to see (and have my security software inspect) the downloaded file BEFORE it is installed (and I may later wish to re-install the file). And the downloaded file which is the updated version of FF DOES NOT SHOW UP in the folder where all downloads are set to go on my machine, NOR does it show in the Tools>Downloads box. SO (1) why is this, (2) where IS it, (3) how to correct this behaviour so it behaves like any other DL and goes where I have set it to go. ?!?

-- (re 2): FOUND where the update probably initially DL's to: C:\Users\Xyz\AppData\Local\Mozilla\updates\AlphabetSoup(may be more than one with same date>inspect each)\updates --- where there is a 'last-update.log' with some details. BUT WHY does the file not DL to where all DL's are set to go to in Preferences ? And besides being hidden in an obscure folder (NOT where DLs are set to go to), the user is not given the chance to scan the file for viruses etc as once the user clicks ok to update, the file is DL'd and installed in one action. ## 'Security' in obscurity is INSECURE ## that is very old not-news, so WHY ????? And this is where the separate-but-related question (above) kicks in too..

re the .mar files, thanks for that, but it doesn't answer my question, and (I'm not a hacker (nor a cracker)) basically saying the .exe is written as some kind of proprietary file instead of an obvious .exe so that presumably only FF can execute it, I'm guessing, doesn't solve the question - see my clarification above.

And btw, if you don't mind my saying, from an English-language pov, saying the update .mar's the original, is probably an unfortunate expression (!), I wonder on the degree of tongue-in-cheekiness of the originator of that extension name...