What is this Shape Key Icon referencing? What is this Shape Key Icon referencing in the Outliner?  Is it the name for the Shape Key data set?
The icon shows that there are shapekeys on that object. The name is normally set to Key with a number suffix if that is already in use, but can be renamed.

In the outliner you can double click the name to change it.

From python you can use bpy.data.shape_keys["Hide.001"].name = "NewName"