User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.122 Safari/537.36

Steps to reproduce:

One of the important use cases for the user-agent string is vulnerability filtering (see: https://github.com/WICG/ua-client-hints#vulnerability-filtering). That is, proxy servers are used to verify that users accessing information are not doing so from browsers/devices that are potentially vulnerable to security issues.

While the major version provides some insight, it is not enough. Both the full browser and OS version are required to ensure that that user is indeed running an up-to-date version.

Given the freeze of the UA string, It would be great to have support in FF for Sec-CH-UA to enable the ability to opt-into receiving the full browser and OS version. Or, have some feature that indicates that the version is out-of-date/vulnerable, while preserving the existing UA information.