Ecosystems:
ActivityPub
Content Security Policy
CSP 3 is being specified in index.bs (published at https://www.w3.org/TR/CSP3/)
CSP 2 is published as a CR at https://www.w3.org/TR/CSP2/.
CSP 1 is published as a Note at https://www.w3.org/TR/2012/CR-CSP-20121115/