Most of the recent takedowns from Roskomnadzor seem to be aimed at illegal gambling sites using github for hosting. Almost all of the rest are for deleted gists, so there's no telling what used to be there. I found one surviving gist and it was a list of suicide methods, written in Russian[1]. The only other takedown requests that were still intact were for references to the Hydra marketplace (which I assume many of the gists also referred to), and, amusingly, for a guide on how to dodge Russian conscription[2].

[1]: The same text from what I assume is the original repo: https://github.com/russian-suicide/ololo

[2]: https://wm2ch.github.io/wm2ch/

Yes, Github is blocked in China