The browser would know if it had a content hash proxy configured and then could use it for all content hashed data. The issue becomes getting people to use one,

The browser would know if it had a content hash proxy configured and then could use it for all content hashed data. The issue becomes getting people to use one, but partial uptake is better than nothing. You could at least get most corporate and education environments with some equivalent to WPAD[1], and maybe even some consumer-level ISPs the same way if they want to reduce the traffic over their network. [1] https://en.wikipedia.org/wiki/Web_Proxy_Auto-Discovery_Protocol https://en.wikipedia.org/wiki/Web_Proxy_Auto-Discovery_Proto...