You interpreted it right. There are dependencies on other repositories in the rust-lang GitHub organization. The optional dependencies for the backtrace featur

You interpreted it right. There are dependencies on other repositories in the rust-lang GitHub organization. The optional dependencies for the backtrace feature include libraries outside the rust-lang GitHub org. https://news.ycombinator.com/item?id=35350600 https://news.ycombinator.com/item?id=35350600