Copr user reported that F23 packages on PPC64LE are not signed:

DEBUG util.py:377: tar ppc64le 2:1.28-6.fc23 fedora 948 k
DEBUG util.py:377: trousers ppc64le 0.3.13-5.fc23 fedora 141 k
DEBUG util.py:377: trousers-lib ppc64le 0.3.13-5.fc23 fedora 165 k
DEBUG util.py:377: tzdata noarch 2015e-1.fc23 fedora 422 k
DEBUG util.py:377: unzip ppc64le 6.0-22.fc23 fedora 178 k
DEBUG util.py:377: ustr ppc64le 1.0.4-18.fc22 fedora 96 k
DEBUG util.py:377: util-linux ppc64le 2.26.2-3.fc23 fedora 2.1 M
DEBUG util.py:377: which ppc64le 2.20-12.fc23 fedora 47 k
DEBUG util.py:377: xkeyboard-config noarch 2.15-2.fc23 fedora 760 k
DEBUG util.py:377: xz ppc64le 5.2.1-3.fc23 fedora 150 k
DEBUG util.py:377: xz-libs ppc64le 5.2.1-3.fc23 fedora 107 k
DEBUG util.py:377: zip ppc64le 3.0-15.fc23 fedora 269 k
DEBUG util.py:377: zlib ppc64le 1.2.8-8.fc23 fedora 98 k
DEBUG util.py:377: Transaction Summary
DEBUG util.py:377: ================================================================================
DEBUG util.py:377: Install 222 Packages
DEBUG util.py:377: Total download size: 141 M
DEBUG util.py:377: Installed size: 590 M
DEBUG util.py:377: Downloading Packages:
DEBUG util.py:377: --------------------------------------------------------------------------------
DEBUG util.py:377: Total 23 MB/s | 141 MB 00:06
DEBUG util.py:377: Error: Package tar-1.28-6.fc23.ppc64le.rpm is not signed

Full log is here:
https://copr-be.cloud.fedoraproject.org/results/thofmann/openrave/fedora-23-ppc64le/00108540-fparser/root.log