Edge: https://developer.microsoft.com/en-us/microsoft-edge/platform/status/fidou2f/?q=U2F Not planned.
Firefox: Security/CryptoEngineering - MozillaWiki Supported in 57.
Safari: GitHub - Safari-FIDO-U2F/Safari-FIDO-U2F: FIDO U2F support for Safari. · GitHub available via plugin.