Xuan Kong Mi Zhi is about the "Sheng and Ke" of "Wu Xing" (The growth and destruction of the 5 elements). Together with the meaning and interpretation of the Ba Gua. (Yi Xiang).
At the moment as I'm unable to put up in Chinese characters, I'll be temporary writing in "Han Yu Ping Yin".
One example in "MiZhi" is " Bu Zhi Lai Lu, Yan Zhi Ru Lu, Pan Zhong Ba Gua Jie Kong."
There were different explanation or variation of interpretation of the above verse. Generally, this is talking about if one doesn't know the direction of the facing or mountains or sitting. Another is when one doesn't know the direction of the heaven's plate. Then the earth's plate will be useless or empty.
Complementing the above scripts are also "Xuan Ji Fu" and "Fei Xing Fu". Such verses are predictive answers to the different combinations of 9 stars Wu Xing Sheng Ke in different times.