The term "main programmer" refers to the person who has the primary responsibility for writing and managing computer code in a project or team. They are typically in charge of designing, developing, and maintaining the software. Full definition
Back in Japan, Main Programmer Nishida was working on the Super Famicom's capabilities. (nintendowire.com)
The following comes from Nintendo's SNES Classic interviews with F - Zero director Isshin Shimizu, main programmer Yasunari Nishida and designer and Takaya Imamura... (gonintendo.com)
News of the change came during a stream of Mobius Final Fantasy when Lightning Returns: Final Fantasy XIII main programmer Naoki Hamaguchi announced that he would be taking over the project. (techtimes.com)