ext/rustup @21cb05b7-2a22-419f-a180-1d1a1d9c3b63/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.