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This is, in fact, Google Earth's building layer. To see it, go to the layers sidebar and enable "3D buildings".
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Google Earth's layers contain a lot of useful information that enhance the satellite imagery: road names, airports, parks, populated places, pictures and more. The cool thing is that they reside on Google's servers, so you don't need to update Google Earth to see new information. Google Maps could become much more useful if it included these overlays.