ext/rustup @run/763c92b4-8cd4-4141-952a-d240013f3017/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.