Zerodha Client Master Report

why does Zerodha send client master report?

Bcoz sebi mandates them to do so

Explained here: Why did I receive an e-mail from Zerodha with my updated Client Master Report (CMR)?

can you explain this point:

  1. Trading ID mapped to demat account - Mapping of Unique Client Code (UCC) circular ( PDF ) by SEBI mandates mapping trading ID to demat account. Whenever a demat account gets mapped to a trading ID with Zerodha or any other broker, it is classified as a change and an updated CMR is sent.