$ git clone -n https://src.fedoraproject.org/rpms/rust-portpicker.git /var/lib/mock/f45-build-43921-809/root/chroot_tmpdir/scmroot/rust-portpicker
Cloning into '/var/lib/mock/f45-build-43921-809/root/chroot_tmpdir/scmroot/rust-portpicker'...
$ git fetch origin e187acb02e73e9abc71e0cff3126de5fe7b8ccf4:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-portpicker
 * [new ref]         e187acb02e73e9abc71e0cff3126de5fe7b8ccf4 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e187acb Regenerate with rust2rpm v28