That plus the german system of "Zeugnisse", which if you squint you will see that is totally against GDPR and even constitution: whereby you get marked (for life) by your employer with a document that has the same validity as any other public document, they "document" your performance (according to you current boss, anyway, in case you do not have a good relation you don't get a good certificate) in a language which is absolutely in code and not meant to be read by you.

A bad "Zeugniss" could leave you out of the work market for years, and all is needed for that is a boss that does not like you. Moreover, you can only understand that the document implies you are not good by decoding it with special tools in internet.