Looks like the domain name is misspelled; the URL should be:

https://sourceforge.net/projects/xca/

Heh. Once upon a time, school allowed me to choose my preference, the choice being to either use her Majesty's English or American English, but not both. I chose British and stuck to it, but here is an example of where I'm just taking it too far. lol

Thanks for correcting. :-)