This is simply a collection of images (PNG's), including every 'Building' object, and most 'Other' objects. Each image has a grid overlaying the object, with the anchor tile highlighted in yellow.
The primary use of this utility is to show you where the anchor tile of buildings and objects is located. This allows the map copy feature to be used more effectively, since only the anchor tile needs to be selected to copy an entire object. This is very important, for example, when overlapping buildings, as you must not copy over the anchor tiles of existing buildings.
Some buildings and objects are very large (Cathedrals, Wonders, etc). It may be difficult to select the proper tile, since the selection highlight is hidden under the object. Other objects are awkwardly shaped (Flowers, Paths, etc), so it is not clear where the anchor tile would be. This utility shows you exactly where the anchor tiles are, so you can click in exactly the right spot on your first attempt.
More information is given in the READ_ME contained in the file.
Please see my article Advanced Guide to Map Copying in the University Forum. It goes into much more detail as to how and why this utility might be useful.