What does the vehicle outline have to do with this answer option?

inform me about the actual height of the load " which protrudes beyond the vehicle outline " https://www.fuehrerschein-behalten.de/Erklaerungen/was-muessen-sie-beim-betrieb-von-fahrzeugen-hinsichtlich-der-fahrzeughoehe-beachten-2-6-06-101#:~:text=Deshalb%20musst%20du%20dich%20%C3%BCber,H%C3%B6he%20informieren%2C%20bevo before you drive off.&text=The%20maximum%20height%20of%20vehicles%20is,the%20vehicle%20must%20not%20exceed%20this.&text=Should%20you%20carry%20a%20load%20on%20the,the%20actual%20height%20of%20the%20vehicle.