The SPKAC ASN.1 description:

PublicKeyAndChallenge ::= SEQUENCE {
    spki SubjectPublicKeyInfo,
    challenge IA5STRING
}

SignedPublicKeyAndChallenge ::= SEQUENCE {
    publicKeyAndChallenge PublicKeyAndChallenge,
    signatureAlgorithm AlgorithmIdentifier,
    signature BIT STRING
}


What's the point of the challenge string?


Question: IPython Qt Console doesn't have a title in GNOME app switcher
Answer: This is not a solution but I know where the problem comes from.
Gnome Shell uses the WM_CLASS property to associate apps to their ".desktop" files. Reference

IPython Qtconsole's WM_CLASS value is empty and that is why you do not see any title up there. I reported an upstream bug.

You could create a .desktop file without a name that would temporarily fix your problem but any other app with no WM_CLASS property would mapped to that one too.

cp /usr/share/applications/ipython-qtconsole.desktop .local/share/applications/.desktop