Chrome has never supported the FIDO U2F API directly[1]. However, it does ship with an internal extension and it's possible to implement the U2F API by using postMessage to send messages to this extension. (Description continued in comments.) [1] https://fidoalliance.org/specs/fido-u2f-v1.2-ps-20170411/fido-u2f-javascript-api-v1.2-ps-20170411.html