Yes, this was a thing already thirty years ago. There's even a term for them: coded reference letters. I even got a reference letter explicitly declaring that i

Yes, this was a thing already thirty years ago. There's even a term for them: coded reference letters. I even got a reference letter explicitly declaring that it doesn't contain hidden codes. https://www.arbeitszeugnis.de/presse/geheimcodeliste.pdf https://www.arbeitszeugnis.de/presse/geheimcodeliste.pdf (German) This shows that there's a conflict: law forbids to discriminate someone with a bad review of their capability, motivation or fitness. But people always seem to try to work around this prohibition. Like giving a friendly declaration that someone worked at a company if they weren't impressed and give an enthusiastic recommendation in the other case.