$ git clone -n https://src.fedoraproject.org/rpms/rust-derive_builder.git /var/lib/mock/f41-build-side-1-2838080-33742/root/chroot_tmpdir/scmroot/rust-derive_builder
Cloning into '/var/lib/mock/f41-build-side-1-2838080-33742/root/chroot_tmpdir/scmroot/rust-derive_builder'...
$ git fetch origin b454be2733d05ba8fba96fe59cbfd7a0b4f48101:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-derive_builder
 * [new ref]         b454be2733d05ba8fba96fe59cbfd7a0b4f48101 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b454be2 Bump pretty_assertions dev-dependency from 0.6 to 1