The numbers designate the pertinent sections of the UN Charter, the UN Declaration on Principles of International Law, the Taiwan Relations Act, and the UN Law of the Sea Convention, all of which prohibit Chinese military action against Taiwan, whether it is considered independent or a part of China. UN action in the Korean War demonstrated the point. Though it is US domestic law, it deliberately tracks the language and purpose of the Charter. Nations are free to conduct military and naval exercises, but they must do so in a manner that does not interfere with the peaceful use of the sea by others.
International straits are part of the high seas where freedom of navigation is guaranteed to all.
China's 1995 to 1996 live-fire drills, mock amphibious assaults and missile firings against Taiwan violated every one of those provisions of international law, closing the Taiwan Strait and the airspace above it to world commerce. And after the independence movement lost ground in the 1998 elections, China responded not by relaxing its bellicose posture but by deploying hundreds of additional missiles targeted at Taiwan and brandishing its neutron bomb for good measure. Along with an introduction to international law 101, Beijing also needs to unlearn some of its Orwellian logic. War is peace, right out of 1984. If so, it's a perverse understanding of the West's deterrent strategy of preserving peace by preparing for war.