Site, wiki and forums have been closed until a potential future move to a new place. GCstar project can still be found on Gitlab.
I'm really sorry for the inconvenience. The lack of time on my side made the site prone to attacks, as I couldn't update all its components (including the wiki and the forums). So I took the difficult decision to close everything as soon as I discovered many of these attacks as I don't want to take the risk to be personnally responsible for what could result from them. I hope that the forum and the documentation will find a new place soon.
In the meantime, other contributors, especially Kérénoc who's been doing a fantastic job so far, are making their best to make the project still alive. Everything can be found on the project page linked above.