If you're working with an AE SaaS setup, this configuration will connect your Automation Engine (and Imaging Engine) to your Esko Proof Server, so that Imaging Engine can send files to the Proof Server, for proofing on your device.
For more flexibility, you can connect to several Proof Servers, and have access to all the workflows configured on these Proof Servers. When sending files through Imaging Engine's Proof for Content Approval task, you can then select which workflow of which Proof Server you want to use.