Answer:
Chaka joins the NFL after serving as a referee in two college athletic conferences.
Explanation:
The word, "official" as an adjective means "relating to a public body and its activities and responsibilities" ( "Oxford" ). The National Football League (NFL) is a public body and its appointment of Maia Chaka as the first black woman on-field referee is a groundbreaking achievement.
The news that Maia Chaka had joined the National Football is therefore an official news as it relates to her position in serving the public and holding a position of responsibility and service to the public.