Purpose of ICs in EMCA - Type-C
I found the answer for my question:
Do all USB Type C cables support full power delivery


  In order for a USB-PD compliant source to advertise capabilities
  greater than 3A (or up to the full 5A limit of the spec) the Type-C
  cable must be an Electronically Marked Cable Assembly (EMCA) and
  support SOP' packets. It must respond to the "Discover Identity" VDM
  sequence (USB-PD spec section 6.4.4.3.1) with a cable VDO packet with
  bits 6..5 set to indicate 5A current handling capability.