yeymaps comes with different background maps. I can change the background with the small globe symbol in the top right of the map window.
By default, yeymaps is started with the background map of the Open Streetmap Community. However, there is also a background map from Microsoft Bing Maps and an aerial image from Microsoft Bing Maps.
The map display of the LIKA data depends on the zoom level. The further I zoom in on an object, the more details (parcel boundaries, buildings, labels) appear.