public int getMainClassIndex() {
		return main_class_index & 0xffff;
	}
{@code main_class index} must be a valid index into the constant pool. The entry at
that index must be a {@link ConstantPoolClassInfo} structure representing the main
class of the current module.
@return index of main class.
Ghidra/Processors/JVM/src/main/java/ghidra/javaclass/format/attributes/ModuleMainClassAttribute.java