The Static Content rule
This rule adjusts the cacheability settings based on the file extension of requested content.

Criteria
You should carefully review the list of file extensions in the match criteria to make sure they represent cacheable content for subcustomers' sites. Add or remove new extensions as necessary. Only the extensions set here will have the Behaviors in this rule applied in regards to caching.
The Caching behavior
If appropriate, you should also adjust the settings in this rule's Caching behavior. (Settings are identical to the Caching behavior set in the Default Rule.)
The Remove Vary Header behavior
By default, an Edge server fielding a request from a subcustomer site will not cache an object with an HTTP Vary header in the response,
unless that response is a compressed object, and the response headers include both Vary: Accept-Encoding
and Content-Encoding: gzip
headers. If
this is always the case with subcustomers, set this switch to Off.
However, some applications add the HTTP Vary header even when the content does not vary. In that case, set this switch to On to have the Edge server remove the header so that the content may be cached.