It refers to the manpage section. Good SO post: https://unix.stackexchange.com/questions/3586/what-do-the-numbers-in-a-man-page-mean https://unix.stackexchange.

It refers to the manpage section. Good SO post: https://unix.stackexchange.com/questions/3586/what-do-the-numbers-in-a-man-page-mean https://unix.stackexchange.com/questions/3586/what-do-the-nu...