Seems like you’re referring to public GitHub IPTV playlists (e.g., iptv-org) that publish large M3U lists (many projects claim 6–10k channels). The most notable, maintained repository is:
If you’re tired of scrolling through dead links and outdated m3u files, you might want to check this out. I stumbled across a repository that is arguably one of the most comprehensive collections of publicly available IPTV playlists I’ve seen in a while. iptv playlist github 8000 worldwide new