C236 Intensive Cooperation

On the afternoon of October 6th, Zhang Yunfeng, Cousin, Zhang Yunran and Lei Xinlei took a plane back to Yanjing. Before they boarded the plane, Zhang Yunfeng sent an email to Huang Yong, who was far away in Yanjing, to send a huge attachment of about 300 mb. This attachment was developed by the waiter after some consideration. As for what this software was, if it was said out loud