The secret library means at least the mother is a dissident. ONE book could get her in serious trouble, a whole library means, would Anette rat her out, if not prison, expulsion from the social net (she looses her job and does not get another one, and oh, no new kidney for the class traitor = death sentence).

Braunschweig is in the german region "high german" was taken from. So there's basically no dialect there. At least not a very distinguished one, compared to those who a practically a language of their own (bavarian, swabian, frisian …)

You have to remember, this show was (probably) filmed for a german audience. To us, it was blatantly obvious. So much so, that we understand that the real stunner weren't the fully stocked shelves (that's just a lot of colourful packaging), it were the piles of oranges and bananas.

I was a teenanger in the 80s. And as the child of east germans, who defected to the west in 79, this show strums some odd chords with me. There were so much subtle cultural references non-germans probably would miss! I had a blast and some gut wrenching flashbacks …
Cannot wait to see more! ^^

I agree, does not work.
As a german, i can see how a non-native speaker would make this connection and suspect a pun, but as a native, it didn't even occur to me.