I simply love, how meticulously one can document and source facts on #Wikidata, like in this case the official name of #Gaugrehweiler in #Donnersbergkreis, which was called Untergrehweiler, as I found in a source of 1832 and another one of 1922. In the latter one, the name had already changed to the present one. https://www.wikidata.org/wiki/Q642168