BridgeDB still isn't checking DKIM verification results properly
From this commit message for this unittest:
Also, "dunno" certainly isn't a valid DKIM signature.
See the ticket description for legacy/trac#12086 (moved) for how
15:30:31 DEBUG L495:server.lineReceived() > X-DKIM-Authentication-Results: dunno
ended up in the headers on an incoming email in the first place.