PAC marked no-cache / no-store / max-age=0
low
Forbidding caching does not make changes faster in a useful way; it makes every client re-fetch the file on the engine's minimum interval, which adds load on the PAC server and makes the PAC server a per-request dependency on some clients.
Why it matters
PAC changes are rare events; fetches are per client. no-cache or max-age=0 turns a
file that should be fetched hourly into one that some consumers fetch on every network
change or even per request. A short positive max-age (600) gives nearly the same
freshness with a bounded fetch rate and keeps the client working from its cached copy if
the PAC server is briefly unreachable.
How to fix
Use Cache-Control max-age=600 (or longer) instead of no-cache.
Examples
Bad
HTTP/1.1 200 OK
Content-Type: application/x-ns-proxy-autoconfig
Cache-Control: no-cache, no-store
Good
HTTP/1.1 200 OK
Content-Type: application/x-ns-proxy-autoconfig
Cache-Control: max-age=600