Bug reported by @vasild here: (https://github.com/bitcoin-core/gui/pull/86#issuecomment-717789400)
listen=0 will cause us not to listen on any port, so we would not accept any incoming connections, regardless of whether clearnet or Tor.
$ bitcoind ... 2020-10-28T08:41:57Z Config file arg: listen="0" 2020-10-28T08:41:57Z Config file arg: listenonion="1" 2020-10-28T08:41:57Z Config file arg: rpcport="8332" ... 2020-10-28T08:42:19Z tor: Got service ID foo, advertising service foo.onion:8333 2020-10-28T08:42:19Z AddLocal(foo.onion:8333,4)
$ netstat tcp4 0 0 127.0.0.1.8332 . LISTEN
(bitcoind is only listening on the RPC port)
I guess this can be considered as a bug because it will (I guess) advertise
foo.onion:8333where nobody is listening.