We’re going to be doing a HEAD request to https://api.wordpress.org/translations/core/1.0/?version=4.1 on the 4.1 about page, in JavaScript. While the heavy operations performed there are cached in memcache for 15 minutes, I think it may be prudent for us to (temporarily?) cache it at the load balancers to avoid being CPU-bound.
Suggestion: cache OPTIONS and HEAD requests to https://api.wordpress.org/translations/core/1.0/ for a period of time. A minute or 15 minutes is fine, but so is an hour.