There’s a “Repositories” link at the top of the page that links to https://lore.org/#repositories, WhyHow links to various GitHub repos, including https://github.com/EpicGames/lore, which claims to have code for the CLI. I see no reason to suspect that claim is incorrect. The code likely lives in https://github.com/EpicGames/lore/tree/main/lore-client)