A nifty tool that’s quite useful in catching errors in your PAC [proxy auto config] file is “pacparser”. You can find it here:
When encountering an error, it also highlights in which line the error was encountered, leading to easier troubleshooting.
FYI: a pac file is a setting in your browser that instructs the browser which proxy to use. It’s useful for cases where you’d only want to use a proxy conditionally (example only certain site go through proxy A, the rest through proxy B), proxy load balancing and failover, etc
Quite a good PAC file checker.