The goal of this issue is to identify whether the file download tracking works on iOS/Safari. If it does not work, maybe it can be fixed, and if not easy to fix then we could document that it is not working ("Known issue").
from Customer feedback:
Just wanted to provide feedback and corresponding question while trailing Piwik/Matomo. I found (so far) that Piwik/Matomo does not track downloads when using a mobile device (iphone) and safari browser. Is this a known issue?