I see ... Sorry
Here is a list with the codes of some older, not anymore active, airports and airbases:
https://de.wikipedia.org/wiki/Liste_...in_Deutschland
Here you can choose the airbases, and in case they had/have an ICAO code, both (old + new) is displayed:
https://www.forgottenairfields.com/d...categoryId=150
I know, it is not exactly the answer you want, but I will continue with the search.
Wish you a nice evening.