At its core, the Collapsible component is a regular <div> element. Thus, both DOM and React properties, methods, and events are accessible. To read up on all of the possible DOM attributes and types available for div elements, check out this MDN Web Documents page. To learn more about DOM events and methods, you can read more on the MDN Web Events documentation page.
Also, feel free to read about the types of React events available, or see how DOM attributes change in React. Working in tandem with Styled Components, you also have access to the as property.