download.kde.org itself seems to redirect the request to one of the mirrors. Maybe it should go first in the list?
Oh yes you are right! curl http://download.kde.org/stable/frameworks/5.24/attica-5.24.0.tar.xz ~ <!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN"> <html><head> <title>302 Found</title> </head><body> <h1>Found</h1> <p>The document has moved <a href="http://www-ftp.lip6.fr/pub/X11/kde/stable/frameworks/5.24/attica-5.24.0.tar.xz">here</a>.</p> <hr> <address>Apache/2.2.22 (Debian) Server at download.kde.org Port 80</address> </body></html>