InstantCommons in various third-party wikis makes a lot of requests to commons.wikimedia.org, about 50k per minute. Even from a single IP, it can be several thousand. We have to make sure that we don't throttle these requests too much.
Idea:
- treat InstantCommons requests like regular unauthenticated bots (x-trusted-request: D)
- For high-traffic site, register the IP range as a "known client" (x-trusted-request: B)