Notification Center alerted me that an update could not be installed automatically. I assume the reason is that the app the update is for was purchased from another country's App Store using another account.
After clicking on the notificaton this is what made me inhale the sip of coffee i was unfortunately trying to drink at that very moment…
When copying the text into the clipboad and pasting it somewhere, the text becomes readable:
Einige Updates wurden nicht automatisch installiert.
Klicken Sie auf „Installieren“, um sie jetzt zu aktualisieren.
(Which is German and tells me what i already suspected).