$ quassel
Icon theme "oxygen" not found.
Icon theme "oxygen" not found.
Error: standard icon theme "oxygen" not found!
No DockManager available
2017-02-27 10:27:35 Warning: SslServer: Certificate file /home/timo.muehlbach/.config/quassel-irc.org/quasselCert.pem does not exist 
2017-02-27 10:27:35 Warning: SslServer: Unable to set certificate file
           Quassel Core will still work, but cannot provide SSL for client connections.
           Please see http://quassel-irc.org/faq/cert to learn how to enable SSL support. 
2017-02-27 10:27:35 Warning: SslServer: Certificate file /home/timo.muehlbach/.config/quassel-irc.org/quasselCert.pem does not exist 
("QSQLITE")
2017-02-27 10:27:35 Info: SQLite Storage Backend is ready. Quassel Schema Version: 18 
2017-02-27 10:27:35 Info: Restoring previous core state... 
QObject::connect: No such slot BufferViewFilter::_q_sourceDataChanged(QModelIndex, QModelIndex)