Master CDs in the Music Industry


#1

Can someone please tell me about how Master CDs work in the music industry as an album is being finalized? What periods of time were Master CDs used, or are they still used?

Like this CD, for example, that’s labeled “Final Master CD”?
https://m.ebay.com/itm/RARE-PROMO-Robert-Hill-FINAL-MASTER-CD-1998-rock-blues-slide-guitar-Moses-McCord/352181014849?hash=item51ff9fd141:g:BeoAAOSwXKtZznOL