https://developer.wordpress.com/calypso/
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“Open source is the most powerful idea of our generation. I’m proud to take our intellectual property crown jewels and open Calypso up to the world for the community to hack on, play with, poke, prod, and extend and make their own. This is the same spirit of sharing which has allowed WordPress to become a de facto web operating system over the past decade. It may take time, but open will win over closed every time.” – Matt Mullenweg