Delivery Behaviors allow you to control how content is delivered to end-users with headers and forced downloads. The delivery behaviors of your content can be wide ranging and varied, thefore, these policies allow you to get even more specific with how content reaches your customers.
Custom HTTP Response Headers
The Custom HTTP Response Headers policy options allow you enable and bypass certain Origin headers that affect the delivery of content.
Transfer Origin ETag Header
When Custom HTTP Response Headers is enabled, the Origin ETag header is transferred by default. The Origin ETag header is more specific than a modified-date.
Since you could theoretically have two versions of the same file that were created at the same time, the ETag is a way of coordinating freshness with your Origin that may differ from the last-modified header.
Force Download by User Agent
When Force Download by User Agent is enabled, the Origin’s Content-Disposition header is bypassed, and files are forced to download to the user’s hard drive.
When Force Download by User Agent is By default, the Origin’s Content-Disposition header will determine the delivery behavior of files.