The Inspector window is an advanced tool that generally tells you what components exist within or on a selected object. If the object is a seat, it will contain a Seat Position component. If the object is a solid wall, it will have a Collider component so that avatars can't pass through it. If the object contains a Lua script, it will have a Script Runtime component attached to it. These individual components can be examined, managed, and potentially modified via the Inspector window.