Yeah it says that in the article. “A bittering agent (Denatonium Benzoate) has also been applied to the game card,” the spokesperson said, adding that Nintendo

Yeah it says that in the article. “A bittering agent (Denatonium Benzoate) has also been applied to the game card,” the spokesperson said, adding that Nintendo recommends keeping Switch cartridges away from children “to avoid the possibility of accidental ingestion.” It's somewhat common practice, some products will even say "contains a bittering agent to prevent ingestion" somewhere on the container. I believe engine coolants are required to have it.