Field Monitor is an editor extension for Unity (the game engine) that allows you to view the values of fields and properties, both static and ones in object instances. This can be useful for viewing changes to values during play, e.g. the health of the player. This is similar to using the Inspector to view the value of public fields, except you can view fields and properties that are static or private or that don't belong to a MonoBehaviour.
The package will be available for purchased and download from the Unity Asset Store soon.