Source: https://groups.google.com/a/chromium.org/forum/m/#!msg/blink-dev/-2JIRNMWJ7s/yHe4tQNLCgAJ
Status: https://www.chromestatus.com/feature/5704553745874944
From the source...
| Google Chrome Stable Version | Stable promotion | What happens then? |
|----|----|----|
|Chrome 81 | Mid March 2020 | Deprecate access to `navigator.userAgent` |
|Chrome 83 | Early June 2020 | Freeze browser version and unify OS versions |
|Chrome 85 | Mid September 2020 | Unify desktop OS string as a common value for desktop browsers. / Unify mobile OS/device strings as a similarly common value for those at Chrome 85 [For the mobile value, we (Google) may split it further based on common device dimensions, as a one-time exercise, to reduce the compatibility risk of unification.]|
Google is instead planning to use [[https://wicg.github.io/ua-client-hints/|Client Hints]] to provide device information. Other major browser vendors praised the move and will probably follow suit.