I'm not sure what you are referring to with 'such a thing', but mirroring libgen and zlib is really not hard. Libgen offers Torrent links as does Anna's Archive. The libgen domains are fragile, but here's a link to the Anna's Archive torrents: https://annas-archive.org/torrents. They even have a page talking about training LLMs on this data: https://annas-archive.org/llm