[romaniv]

Unless we're talking about different things, cache manifest is an HTML 5 feature designed to enable websites to work offline. That's quite different from HTTP-level caching, which would be applicable to any files/resources and designed primarily with performance and bandwidth savings in mind. I might be unaware of some relevant HTTP 2 features, though.

[bhldr]

Definitely a different thing. This is a HTTP 2 frame, sent by a client

[romaniv]

Could you post a link to the relevant part of the spec or some article dealing with this feature?