$ git clone -n https://src.fedoraproject.org/rpms/rust-shadow-rs.git /var/lib/mock/f40-build-2658049-66917/root/chroot_tmpdir/scmroot/rust-shadow-rs
Cloning into '/var/lib/mock/f40-build-2658049-66917/root/chroot_tmpdir/scmroot/rust-shadow-rs'...
$ git fetch origin 57f6135f5f89060f86a8c1b126093355232af750:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-shadow-rs
 * [new ref]         57f6135f5f89060f86a8c1b126093355232af750 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 57f6135 Bump git2 dependency from 0.13 to 0.18