I downloaded repomd.xml from
download.opensuse.org/tumbleweed/repo/non-oss/repodata/repomd.xml.  That
directory had files for Dec 16th.  When I tried to open one of the file in that
directory (
http://download.opensuse.org/tumbleweed/repo/non-oss/repodata/a424c3aaba9f6e89e900d2c424633e682eb71900a6f32b1e855ad00c8cf03420-filelists.xml.gz
) I was taken to mirrors.edge.kernel.org.  Unfortunately, the latest files in
that directory were from the 14th (today is the 20th).  The above file wasn't
in the outdated mirror.

This prevents download of current releases.  Perhaps before blindly sending us
off to some mirror site, a database should be checked to see what mirrors have
which versions and not send us to a site that doesn't have the files for the
version that repomd references.

This really resolves to 'zero' confidence in the mirror system and low
confidence in being able to download a coherent version of the distribution.