[mikeash]

I'm a bit confused, how does this qualify as "we already have this system" when your step #2 is "update the code in the browser"?

Aside from that, yes, this sounds pretty much like what I'm thinking of.

[ay]

I thought you had in mind a totally new content delivery mechanism to fetch the data by hash from the network, relative to that adding the content addressability to browser cache is near trivial. Apologies if I misunderstood.

[mikeash]

I was thinking that this could be added as well, but that it would be purely optional, if anyone got around to adding it.

Basically, you need the hash and a fallback regular URL. The browser is free to grab the content using the hash however it likes, whether it's grabbing it from its cache, using the fallback URL, using another known URL for that content, or using some new delivery mechanism.