Felipe Borges created an issue:
In addition to #191, we could take some measures to decrease the SEO efficiency of the GitHub repos (it may be that the GitLab repos are currently being "penalized" by search engines for having duplicate content with another website. yes, this is a thing).
According to the GitHub's robots.txt, ONLY "master" branches are getting indexed https://github.com/robots.txt
So one measure we could take is to delete the "master" branches from the GitHub repositories and set a stable one as the default branch. That won't propagate to forks, and for this reason, forks might be scoring well in the search engines results, but this is better than what we have currently anyway. Alternatively, the "master" branches of the GitHub repositories could be renamed.