TL;DR if you never used rsync:// access to download copies of data from our VCS's you can stop paying attention. This has nothing to do with "gentoo rsync mirrors" for ::gentoo, which is a separate service that we are not terminating.
We previously offered rsync:// protocol access to gentoo VCS repositories. We have stopped offering this access. This is another service that had little to no usage according to logs, and has a bunch of legacy dependencies. For VCS content please use anongit.gentoo.org to access content in git, and the vcs history project to access read-only copies of historical cvs data at https://projects.gentoo.org. We have kept completed copies of this data, and if the public data is missing something or is incorrect, please follow up with us. -A