http - What is the difference between no-cache and no-store in Cache-control?

Question

I don't find get the practical difference between Cache-Control:no-store and Cache-Control:no-cache.

As far as I know, no-store means that no cache device is allowed to cache that response. In the other hand, no-cache means that no cache device is allowed to serve a cached response without validate it first with the source. But what is that validation about? Conditional get?

What if a response has no-cache, but it has no Last-Modified or ETag?

Regards.

Answer 1

See the below flow chart for better understanding

Ref: (https://developers.google.com/web/fundamentals/performance/optimizing-content-efficiency/http-caching?hl=en#cache-control)