Looks like svn.wikimedia.org was restructured. At the moment, it points to the "formey" server which also host gerrit.
The viewvc tool is no more reachable : https://svn.wikimedia.org/viewvc/mediawiki/trunk/
We have it linked from www.mediawiki.org main page. Did someone forgot to reinstall viewvc? :-)
Version: unspecified
Severity: normal