A few words for my non-German readers:
German employers issue work certificates or references. These certificates are written in pretty much a standard language. The rules on how to write the certificates are mostly unwritten, but very well known to German HR professionals. Certificates can be two pages long. Sentences formulated in a certain way mean something to an HR professional that the untrained eye cannot see.
A company specialising in Machine Learning is now offering a tool to read those certificates and make them understandable to non-HR professionals.
I recommend using google chrome extension for an automated translation of the web pages into English.