For the purpose of making the Rollup model easier to understand and easier to dissect, Celestia researcher NashQ divided Rollup's Sequencer into two logical entities - the Aggregator and the Header Generator. At the same time, he divided the transaction sequencing process into three logical steps: inclusion, ordering, and execution (inclusion, ordering, and execution).
Guided by this analytical mindset, the six important variants of Sovereign Rollup become clearer and more understandable.