The reason for the restrictions was unclear but it would disrupt Taiwan's northern flight information region (FIR). So far, China has refrained from commenting on the matter while Taiwan's defence ministry has said that they are looking into verifying the information, with perhaps it involving space activities by China such as satellite launches.
Well, that's a wee bit coincidental if that were to be the case. For some context, the area identified is about 85 nautical miles north of Taiwan. It might not be anything but it is worth keeping an eye out on the developments here.