More link: https://displaytypefont.com/product/dunkelheit/
This fonts are authors' property, and are either shareware, demo versions or public domain. The licence mentioned above the download button is just an indication. Please look at the readme-files in the archives or check the indicated author's website for details, and contact him if in doubt. If no author/licence is indicated that's because we don't have information, that doesn't mean it's free.
If you want the full version and license for commercial use,
you can purchase here :
https://displaytypefont.com/product/dunkelheit/
File Font Version :
1. Dunkelheit.otf
2. Dunkelheit.ttf
3. Dunkelheit.woff
4. Dunkelheit Italic.otf
5. Dunkelheit Italic.ttf
6. Dunkelheit Italic.woff