shift + 8 -> (
shift + 9 -> )
alt + ctrl + 8 -> [
alt + ctrl + 9 -> ]
alt + ctrl + 7 -> {
alt + ctrl + 0 -> }
Alternatively alt + ctrl can be replaced by altgr.
And for further fun:
alt + ctrl + ß -> \
shift + 0 -> =
shift + 7 -> /
Actually, it is probably easier to link the whole layout: https://de.wikipedia.org/wiki/DIN_2137#/media/Datei:Deutsche...
It is pretty bad for programming in languages that make heavy usage of braces/brackets/parenthesis.