The story of Cardinal Pole and his cathedral tomb is told here.
Two features in the Precincts are relevant:
Cardinal Pole's coat of arms displayed on the wall on the right on entering the Mint Yard entrance (Image 1)
the stained glass window in the King's School chapel commemorating the generosity of Cardinal Pole to their school (Image 2)
Heraldic rules governing ecclesiastical headware specify that: a full cardinal warrants a red hat and 30 red tassels; a patriarch a green hat and 30 green tassels; an archbishop a green hat and 20 green tassels; and a bishop a green hat and 12 green tassels. If you see a red hat, 30 red tassels and two crossed keys, this indicates a 'camarlingo' ie a cardinal carrying out the duties of a pope during the period of a papal election. All these have been observed more strictly in Italy, France and Spain than they have in England, where the mitre has been regarded as the heraldic device of a bishop. The existence of arms for the see of Canterbury add a further complicating factor.
This raises unanswered queries regarding Cardinal Pole, who seems to get just 20 tassels in the Mint Yard and school chapel, but the full 30 tassels in the Corona (Image 3). Why?
Sources: Neubecker (1976)