What Type 003's flight-deck covers concealed

Why were long sections of the newly launched Type 003 carrier's flight deck covered?

They concealed the catapult machinery and kept observers from confirming whether the launch system was electromagnetic or steam-powered.

When China's Type 003 carrier was newly launched, long black covers hid sections of the flight deck. They concealed the catapult launch machinery and kept observers from determining whether the installed system was electromagnetic or steam-powered. The imagery therefore illustrates how a navy can conceal a key aviation capability in plain sight during fitting-out.