The dgm20.xyz is a ASCII-GRID of the digital elevation model and covers the area of the Free State of Saxony (Germany). 
The file is the merged and sorted data of the DGM20-dataset which can be downloaded here: https://www.geodaten.sachsen.de/downloadbereich-dgm25-4162.html

Spatial reference: UTRS89_UTM33 (EPSG: 25833)

Legal stuff: https://www.geodaten.sachsen.de/rechtsgrundlagen-und-nutzungsbedingungen-4509.html

Quelle: GeoSN, dl-de/by-2-0 (https://www.govdata.de/dl-de/by-2-0), DGM20

10/2019