You will most likely encounter this string in the following scenarios:

– Check which process wrote the log. Use grep -r "proxy-url-file" /var/log/ on Linux or findstr /s "proxy-url-file" C:\Windows\System32\config (as admin) on Windows.

: This workflow was so fundamental that early versions of PortableApps.com's Firefox were built specifically to leverage file:/// PAC files for users moving between home and work networks. Developers experimented with alternative prefixes like resource:///proxy.pac when file:/// faced parsing issues.