A Deliverable of the Private Advertising Technology Working Group of W3C.
Attribution is the name given to the measurement system used in advertising. It is called attribution because it seeks to attribute value from an outcome (like someone buying stuff) to advertisements.
This repository contains a specification that describes an API that would be presented by a browser to websites.
The specification contains all of the details. There is no explainer. All the explanation can be found up front, before it gets into the gory details.