$ git clone -n https://src.fedoraproject.org/rpms/rustup.git /var/lib/mock/f41-build-side-1-2953121-35536/root/chroot_tmpdir/scmroot/rustup
Cloning into '/var/lib/mock/f41-build-side-1-2953121-35536/root/chroot_tmpdir/scmroot/rustup'...
$ git fetch origin 678670744486da8b8f7cfcc16a0f014c2d2e6af4:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rustup
 * [new ref]         678670744486da8b8f7cfcc16a0f014c2d2e6af4 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6786707 Bump fs_at dependency from 0.1 to 0.2