ext/rustup @4c128e93-5432-4178-b3c8-3e176ad32f81/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.