Dear Mr.Dan, usually a firefox update with minor changes comes in at 15-20 mb. Bye

Thanks... I'll see your "usually" and raise you one question ==> How can I know from one update to another? I can deal with the '15-20 mb' "usually" answer. I was looking for real data like I see when apps have updates on my phone. Thanks again.

I send this link:

https://support.mozilla.org/en-US/kb/update-firefox-latest-release

as you can see in the link below, during the update firefox updates you on the amount of data downloaded.

I hope I have been helpful

Thanks for the link. One line in the linked file says "The About Mozilla Firefox window opens. Firefox will check for updates and download them automatically." That's not what I want. If the update is 392MB, for instance, I don't want it automatically downloaded. You wrote "during the update firefox updates you on the amount of data downloaded." Can you see that this is too late? It means I have to be doing a large download before I can know how big it is. This is like having to buy a car to learn how much it costs.

Here you can see download sizes of the recent update: https://ftp.mozilla.org/pub/firefox/releases/86.0/update/win64/en-US/

Most likely you get 12 MB, when you skip one version it's 22MB. When something goes wrong, full update of 56MB will be downloaded.

I can work with that. Thank you. Dan