I tried running feediverse with some feeds configured and it exited without publishing anything - and adding -v didn't show me what was going on.
Eventually I hacked in enough print statements to get this output:
feed obj is {'bozo': True, 'entries': [], 'feed': {}, 'headers': {}, 'bozo_exception': URLError(SSLCertVerificationError(1, '[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:997)'))}
It looks like feedparser returned that error in a dictionary that included an empty "entries": [] array - so feediverse failed silently rather than showing the error.
As for the error itself... I managed to fix that by adding the following to the top of feediverse.py:
import ssl
ssl._create_default_https_context=ssl._create_unverified_context
Based on this StackOveflow tip: https://stackoverflow.com/questions/40666767/how-to-fix-ssl-certificate-verify-failed-feedparser