Paragraph: Treatment of benzene with CO / HCl in the presence of...

Paragraph: Treatment of benzene with $CO / HCl$ in the presence of anhydrous ${AlCl}_{3} / CuCl$ followed by reaction with ${Ac}_{2}O / NaOAc$ gives compound $X$ as the major product. Compound $X$ upon reaction with ${Br}_{2} / {Na}_{2}{CO}_{3}$ , followed by heating at $473K$ with moist $KOH$ furnishes $Y$ as the major product. Reaction of $X$ with ${H}_{2} / Pd - C$ , followed by ${H}_{3}{PO}_{4}$ treatment gives $Z$ as the major product

Question : The compound Z is