[2020] 19.2 stable or "Latest_experimental available" not showing up under Beta tab.

The Latest stable is always to opt out of all betas. All stables listed in the beta tab are old versions; which is why it ends at 19.1. 19.2 is currently the latest, so it is not old.

Latest experimental is not currently listed because 19.2 went stable, and there is not yet an experimental build of 19.3 available to the public. When there is, latest experimental will reappear.