The existing link points to https://github.com/varnish/varnish-modules/blob/master/docs/cookie.rst
and the working link is https://github.com/varnish/varnish-modules/blob/master/docs/vmod_cookie.rst.

This should allow us to close issue 3065 in Varnish Cache.

The release was part of the VSV early September, and is part of
our LTS series.