German lawyers are ecstatic over copyright issues. Soon they will form human centipede and demand 1000 EUR from everyone whose address they'll put their hands on.
They will only send letters to people who cannot defend themselves.
If the open source developer hires a lawyer I'm sure they'd be happy to make them some money. I wouldn't be surprised if they already got contacted. There are a lot of German lawyers out there looking for "victims" to sue on their behalf.