I think it is due to a reshuffle of Austrian SOTA summits, but according to the current database, there is only one summit in the Vienna (Wien) region, WI-001, Hermannskogel. I guess that made the choice of which peak to activate easy.
The Hermannskogel is the highest point near Vienna, and up to World War I, served as the cartographic zero point for Austria-Hungary. The Habsburgwarte, pictured here, is a rebuilt stone tower that sits on top of the hill and sports a variety of antennas and radomes.






