gng.dsun.org no longer exists?

[breun]

Describe the bug
The 'About' section on https://github.com/gdubw/gng contains a link to https://gng.dsun.org/, but at least currently that page is not loading for me. Does this website still exist? If not, this link should probably be removed.

To Reproduce
Steps to reproduce the behavior:

1. Go to https://github.com/gdubw/gng
2. Click on gng.dsun.org in the 'About' section
3. See error in your browser

Expected behavior
I expected to visit a website with more information about GNG.