Autofill Assistant is an execution engine to run user journeys on websites given a set of actions. These actions include clicking on buttons or scrolling to an element. They also provide a way to interact with the user or get input to advance in the flow.
For a design overview see this link. More information about the team can be found here.
The bug component is UI>Browser>Autofill>Assistant and the team email autofill_assistant@google.com.