Repeater Coverage Maps
The coverage maps are field strength contours referenced to decibels over one microvolt per meter (dBuV/m). the lower the field strength the harder it will be to hear the repeater at that location on the map.
The file format is kml-super-overlays zipped into KMZ files for Google Earth. While the files themselves are somewhat large for performance reasons they don't completely load up in Google Earth all at once, for further info see Google's documentation on the subject.
It should be noted that this is a work in progress and there will be improvements made later on.