The developer working on integrating network display functionality into GNOME Shell shared short video clip to the GNOME sub-reddit […] the feature adds a “screencast” button to the row of actions in the Quick Settings menu. Clicking this opens a modal picker where the user can select any Miracast or Chromecast compatible displays on the network.
I thought this was going to be a screen recording tool. Like sharex. Having cast feature is cool as well though.