Hi Filip, what do you consider to be a download? Would that be only files that trigger the Open/Save dialog, or go into the Temp or Download folder, or would it also include files that Firefox displays such as images and videos?

I don't know whether there are any add-ons that offer a feature to block these various types of content, but it's certainly possible. If you haven't already, you can search here: https://addons.mozilla.org/firefox/extensions/

Hi, only files that trigger Open/Save dialog and go into the Download folder.

I used one add-on and it's incompatible with quantum version of firefox.

Maybe lock the download folder to a specific folder and make sure that no write access is possible to this folder. This might have to include the temp folder that Firefox uses by default to store files temporarily or make sure to cleanup this folder regularly.

• https://developer.mozilla.org/en-US/Firefox/Enterprise_deployment

Extensions can inspect the response headers that are associated with a server response.

https://developer.mozilla.org/Add-ons/WebExtensions/API/webRequest

So an extension can look at these two headers --

• content-disposition: attachment indicates an intended download
• content-type may be something Firefox cannot display, such as a Word document or .mov video file

-- and cancel a request based on what it sees. (This may or may not save on bandwidth because Firefox might keep receiving packets in the background while the analysis is done.)

So I think someone could create an extension to cancel requests when the server is sending something that isn't on a short list of allowed content types, or is a forced download. But has anyone done that or will anyone do that? Your guess is as good as mine.