Hyperlink GitHubPagesForGAP in Initial Setup directs to 404

[DominikBernhardt]

Clicking the hyperlink GitHubPagesForGAP in the Initial setup section in README.md directs me to a Page stating

404 This is not the web page you are looking for.

[fingolfin]

That's bizarre. It used to work. For some reason, GitHub actually replaces the correct link in the .md file with garbage. No idea why.