Looks like the license is open:  https://dataforsyningen.dk/asset/PDF/rettigheder_vilkaar/Vilk%C3%A5r%20for%20brug%20af%20frie%20geografiske%20data.pdf
and there is a WMS link here:
https://api.dataforsyningen.dk/wms/gl_aabent_land?service=WMS&request=GetCapabilities&token=
only the WMS is not responding for me 