Char (*(*x())[]) ()

This looks like an evil example straight from the 2nd edition of Kernighan and Ritchie (The C Programming Language), p. 122 (section 5.12: Complicated Declarations), where it is described as a function returning a pointer to an array of pointers to functions returning char. Here is a usage example:

#include <stdio.h>

char x1() { return 'a'; } // Function returning a char-----1
char (*x2[])() = {&x1}; // Array of pointers to functions returning char------2

char (*(*x())[])() { return &x2; } // Function returning a pointer to the above----3

// 分析：将*x()看做一个整体==XX，则上式等价于char (*XX[])() ，这样3式就转化为2式，只是XX为函数指针

// so:x是一个函数，它返回一个指针，该指针指向一个一维数组，该一维数组的元素为指针，这些指针分别指向函数，这些函数的返回值维char类型

void main()
{
    char (*x3)() = **x(); // Pointer to a function returning char
    printf("This is the value: %c\n", x3());
}

Alternatively, you could skip declaring x3 altogether and just write

printf("This is the value: %c\n", ((*(x()))[0])());