Please clarify HTTP Repsonse Vary

[nickchomey]

THis is from Chapter 6

The solution to this problem is to use the HTTP Response Vary header and call out the htmx headers that you are using to determine what content you are returning. A full explanation of HTTP Caching is beyond the scope of this book, but the MDN article on the topic is quite good, and the htmx documentation discusses this issue as well.

There's no need to do a deep-dive into HTTP caching, but it would be great if you could add just a line or two about how to use Vary in this context. Likewise in the HTMX docs. Its not at all clear to me (even after consulting MDN) how to use it.