Intl Enumeration API Specification is a new ECMA402 Stage 3 proposal which lists supported values of options in pre-existing API.
https://github.com/tc39/proposal-intl-enumeration#motivation
Docs: design doc https://docs.google.com/document/d/1lbj_YVW-xhzYNMQeHB-qDjVkf4SA-eTHYpYXx3Oaud8 Update slides for TC39 2021-Dec-15 https://docs.google.com/presentation/d/1wR8Yg3JVwa1RAPgQGqUPsRtP0EeMXy_Q8zqgRIKRiQI
Explainers: https://github.com/tc39/proposal-intl-enumeration