That sounds like a great idea until you download a zip bomb

As an IT Engineer this concept frankly terrified me and feels like your opening yourself up to a potential zero click attack - such as https://threatpost.com/apple-mail-zero-click-security-vulnerability/165238/

So my initial answer is an emphatic "please do not the ZIP". It could be as mundane as a ZIP bomb, or it could explain a vulnerability in the operating system or automatic extraction program. Having a human required to open the ZIP prior to its expansion reduces its attack surface area somewhat (but not eliminates it) because it allows the human to go "huh this ZIP looks funny" if something is off, rather than just dispatching an automated task.

With that out of the way - what's your use case with this? There has to be a specific reason your interested in saving a few clips here on one highly specific archive format, but not others like the tar unix archive, 7z, or RAR.

If this werent a firefox question id say wget url | tar -xvf

You could write a bash script using inotifywait to watch for new files in your download folder and extract them if they are archives.

I think it needs to be done by the operating system, extensions nowadays don't have the permissions to do that.

When I was using MacOS it automatically extract zipped files and I hated it so much, you accidentally click on a link, it automatically saves in download and automatically unzip it, leading to too much trash in downloads...

Unpackerr is usually used for unzipping files downloaded automatically by Radar or Sonarr, but it can also be configured to point to any folder, like your downloads. It’s fairly easy to set up, especially if you’re just pointing it to a folder.

I wouldn't but Firefox has a Files and Applications menu where you can set what actions it performs on downloading a file. You could set that to automatically open with an zip extracting program or a batch file / bash script.

But safari's "feature" sounds dangerous to me - it would be a good vector to attack a system - also just bloody annoying. I wouldn't want the content of my zip files spewed all over my downloads folder.

But yes Firefox can hand any downloaded file over to another program on download if you want to go that way. I don't think it can run an executable though, although again you could probably write a batch file to do that on windows (and possibly a bash script on m Linux) if you like living dangerously.

But just because you can do something doesn't mean you should.