$ git clone -n https://src.fedoraproject.org/rpms/rust-gix-refspec.git /var/lib/mock/f40-build-1794083-24862/root/chroot_tmpdir/scmroot/rust-gix-refspec
Cloning into '/var/lib/mock/f40-build-1794083-24862/root/chroot_tmpdir/scmroot/rust-gix-refspec'...
$ git fetch origin 72b88825be4e066e15a3305b98ea04dadbaacc0e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-gix-refspec
 * [new ref]         72b88825be4e066e15a3305b98ea04dadbaacc0e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 72b8882 Update to version 0.23.1 (rhbz#2299583)