UrhG § 69b is the regulation specifically for software developers that work contracts typically refer to. Usually there is also a clause referring to UrhG § 31a to license usage rights of unknown kinds of usage as well.

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btw. seems that I was wrong about copyright attribution. Got a mail, apparently some contracts include a clause that the employer can in fact attribute any work to herself, so "Copyright (c) 1871 Foobar GmbH" can happen and can be correct.