In English, the term "squarehead" used to refer to Germans and Scandiavians (1), due to their supposedly unusual cranial features (2, 3)
Does the German language have words for the stereotypically British, the stereotypically German (as shown) or other skull shapes?
Sources:
(1) https://www.merriam-webster.com/dictionary/squarehead
(2) https://www.urbandictionary.com/define.php?term=squarehead (I realize that urbandictionary is not a great source, but it has the only explanation of the etymology of the slur that I could find)
(3) https://www.alamy.com/stock-photo-comparison-of-british-german-skull-shapes-ww1-56691744.html (I do not know if this was an actual propaganda poster during WWI, but this is what they claim)