An interview over at Dengeki Online with Hiroshi Matsuyama (CyberConnect2's .hack), Reki Kawahara (Sword Art Online), and Takasuke Futami (producer at Bandai Namco Entertainment) hold an interview discussing the collaboration crossover event with .hack//New World and Sword Art Online Code Register.

https://dengekionline.com/elem/000/001/232/1232871/