There are several reasons why the cat cage is covered with a cloth:
1. Block the cat's vision and interfere with its perception of the outside world. When a cat is in a cage, the shaking of the cage can easily frighten it. Covering the cage with a cloth will prevent the cat from seeing the outside environment and thus reduce its fear.
2. Cats are very sensitive to heat, especially in summer, and are very prone to heatstroke. Covering the cage with a cloth to block out sunlight can help them stay cool.
3. When the owner is resting, covering the cage can help an active cat quickly enter a resting state.
4. Cats can sometimes be very energetic, so covering the cage can also help to reduce noise. 
What to do if your cat has heatstroke:
1. Move the cat to a cool place. If the cat is suffering from heatstroke outdoors, it needs to be moved to a cool, well-ventilated place immediately. If the cat is suffering from heatstroke indoors, the windows need to be opened immediately to ventilate the room or the air conditioner needs to be turned on.
2. Wipe the cat's paws with alcohol. Since cats can only dissipate heat through their paws and breathing, wiping their paws with alcohol after they suffer from heatstroke can quickly and effectively cool them down.
3. Use ice packs or damp towels to cool the cat's body. It's best to wrap the cat's entire body in a damp towel, or wrap ice cubes in a towel and place them on the cat's head, neck, armpits, and inner thighs to help lower the cat's body temperature below 39°C. It's important to monitor the cat's temperature closely while cooling it down, otherwise, rapid cooling may cause hypothermia. Use the cat's rectal temperature as the primary indicator.
4. Encourage your cat to drink more water. If your cat doesn't like to drink water, you can soak the cat food in water before feeding it to your cat, which will increase its water intake.
5. Take your cat to the vet promptly. After emergency treatment and once your cat has recovered somewhat, it's best to take it to the vet for a check-up. Especially if your cat shows signs of dehydration, it's crucial to get it rehydrated immediately. If your cat has severe heatstroke, seek veterinary care immediately.
