I have a source rpm (non-fedora).
It has no signature.
I tried to run rpm -ivh --nosignature xdfr-2.0.1.src.rpm
but rpm exits with error message:
error: xdfr-2.0.1.src.rpm: rpmReadSignature failed: sigh load: BAD
error: xdfe-2.0.1.src.rpm cannot be installed