What is the main function of out-of-the-box Data Processing Engine jobs in Rebate Management?

Data Processing Engine (DPE) is a feature of Rebate Management that allows you to transform data that is available in your Salesforce org and write back the transformation results as new or updated records. You can use DPE to process data for standard and custom objects. Rebate Management has DPE templates that you can clone and customize to suit your business needs. The templates either help you to aggregate transactions by different criteria, or help you to manage other rebate processes. The out-of-the-box DPE jobs in Rebate Management use the templates to query, extract, filter and aggregate journal transactions based on the eligibility criteria and calculation definitions of the rebate types. The aggregated data is then stored in the Rebate Member Product Aggregate object, which is used to calculate the payouts for the program members. References: Data Processing Engine in Rebate Management | Salesforce Trailhead Module, Data Processing Engine Templates with Rebate Management - Salesforce, Data Processing Engine | Rebate Management Developer Guide | Salesforce Developers, Data Processing Engine, Batch Management, and Invocable Actions | Rebate Management Developer Guide | Salesforce Developers