The Scene view control bar lets you choose various options for viewing the Scene and also control whether lighting and audio are enabled. These controls only affect the Scene view during development and have no effect on the built game.
The first drop-down menu selects which Draw Mode will be used to depict the Scene. The available options are:
These modes let you view each of the elements of the G-buffer (Albedo, Specular, Smoothness and Normal) in isolation. See documentation on Deferred Shading for more information.
The following modes are available to help visualise aspects of the Global Illumination system: UV Charts, Systems, Albedo, Emissive, Irradiance, Directionality, Baked, Clustering and Lit Clustering. See documentation on GI Visualisations for informaiton about each of these modes.
To the right of the Render Mode menu are three buttons that switch certain Scene view options on or off:
The menu (activated by the small mountain icon to the right of the Audio button) has options to enable or disable rendering effects in the Scene view.
The Effects button itself acts as a switch that enables or disables all the effects at once.
The Gizmos menu contains lots of options for how objects, icons, and gizmos are displayed. This menu is available in both the Scene view and the Game view. See documentation on the Gizmos Menu manual page for more information.
The rightmost item on the control bar is a search box that lets you filter items in the Scene view by their names and/or types (you can select which with the small menu at the left of the search box). The set of items that match the search filter are also be shown in the Hierarchy view which, by default, is located to the left of the Scene view.