Comment 4 for bug 1881040

I have managed to reproduce the problem, I'm attaching a test script that attempts to download a file to a location that's not permitted by snapd's strict confinement.

What happens is that the chromium snap is strictly confined, so it can't write files anywhere on the filesystem. In my test I'm setting the downloadPath to $HOME/.local, and the resulting apparmor denial is:

  juin 12 16:35:24 bribon audit[35815]: AVC apparmor="DENIED" operation="mknod" profile="snap.chromium.chromedriver" name="/home/osomon/.local/linux-5.7.2.tar.xz.crdownload" pid=35815 comm="ThreadPoolForeg" requested_mask="c" denied_mask="c" fsuid=1000 ouid=1000

I'm afraid you will need to update your tests to download files somewhere they can be written (anywhere in your home directory that's not a hidden folder, or under /media or /mnt, for example).