Explanation:

Box 1: internal
caching-type
Choose between the following values of the attribute:
* internal to use the built-in API Management cache,
* external to use the external cache as Azure Cache for Redis
* prefer-external to use external cache if configured or internal cache otherwise.
Box 2: private
downstream-caching-type
This attribute must be set to one of the following values.
* none - downstream caching is not allowed.
* private - downstream private caching is allowed.
* public - private and shared downstream caching is allowed.
Box 3: Authorization
<vary-by-header>Authorization</vary-by-header>
<!-- should be present when allow-private-response-caching is "true"--> Note: Start caching responses per value of specified header, such as Accept, Accept-Charset, Accept- Encoding, Accept-Language, Authorization, Expect, From, Host, If-Match Reference:
https://docs.microsoft.com/en-us/azure/api-management/api-management-caching-policies