I could see no particular file in the logs. Files were downloaded straight from the iTunes Store and iTunes Match.
However do see some CURL errors which appears related to UPnP. Router/FW is pfSense 2.4.4-RELEASE-p3. Nothing really explains why the web server is going offline but it does after running freshing metadata. I do also note there’s a lot of TCP/UDP ports opened to the loopback address in this process. Looks similar to Internet continues to drop out when running PMS on macOS Catalina.