ext/rustup @b5725347-6775-46c3-9c5d-8168e596d538/main

The path at ext/rustup contains a submodule, revision c31b781f1a50f4aa20c2d1b8f9aa661f1fcd4c40. It can be checked out from https://salsa.debian.org/rust-team/rustup.git.