This location was where the 5.99 binaries were available and, briefly after 6.0 was tagged, 6.99 was also available for download. This area automatically purges old files so I think the error means that no builds are available.
TheJenkins server here (think this is the Right one)
Yup that looks like the right server. At the time of writing the last successful build was 19 days ago. It would be nice if someone was to get it back up and ticking.
A cursory scan through the logs looks like the bit that one would strictly call the build is OK, but that it falls over at the copying files around, packaging, and tidying up phase right at the end. i.e. It’s a build system admin issue rather than the actual KiCad build failing. But as I say, only a cursory look at a build setup I don’t know so I could be way off mark.