2016 Audi A4 2.0 TFSI quattro

A

Scratch

U

Dent

W

Wavy panel — sign of past bodywork / repair

S

Rust

C

Corrosion

B

Dent with scratch

P

Paint mark / touch-up

Y

Crack or hole (bumpers, plastic trim)

X

Part should be replaced

XX

Part already replaced

G

Stone chip on glass

R

Windshield crack — repaired

The number is the severity: 1 is minor (usually cosmetic), 3 is large. Grade-1 marks are normal on used cars.