The yellow code is for people who have reported fever, shortness of breath and respiratory symptoms themselves, so it will not turn yellow.
Travel card is a common travel voucher, which can show where you have been in the past 14 days, and show your travel trajectory, which is beneficial to epidemic prevention and control. Some travel cards have asterisks. Generally, this kind of travel card has been to medium and high risk areas, but it is not necessary to go to medium and high risk areas, so the travel card may not change color and turn yellow.