At 'Main menu' > 'Settings' > 'User interface' there are missing letters at the German translation.
At file Factorio > data > core > locale > de > core.cfg
line 2689 should be:
change-quickbar-by-clicking-with-item=Klick mit Gegenstand legt Schnellleisten-Filter fest (instead of "[...] Schnelleisten-Filter [...]")
line 2690 should be:
change-quickbar-by-clicking-with-item-controller=Schnellleisten-Filter durch Auswählen mit einem Gegenstand festlegen (instead of "[...] Schnelleisten-Filter [...]")
[2.0.28] Missing letter in German translation
Re: [2.0.28] Missing letter in German translation
thx for the report, fixed for the next release