Once more a german state (Bundesland) added another date to be a public holiday. This time it is Thüringen. In 2019 they declared the Children’s Day (Weltkindertag) to be a public holiday. So September 20th is now a free day there.
Seems as if the list of public holiday had been stable for more or less 60 years in Germany, but roughly since 10 years the states are adding more and more exceptions.
I added that day to my library feiertage.