spy bug

HI! I am new to electronics .planning to do fm bug for college project can someone explain this circuit in detail

hey guys i,m new to this forum and Lt spice I am planning on building a FM bug using hardware, i am trying to simulate this circuit using LTspice In simulation i am replacing the microphone with a voltage source of 10mV and 2kHz then removing 68k resistor. simulation file is attched.Kindly...