What mean the "(2)" for the umask?

Git for Windows.
I am reading this documentation about the git init command:

--shared[=(false|true|umask|group|all|world|everybody|0xxx)]
Specify that the Git repository is to be shared amongst several users. This allows users belonging to the same group to push into that repository. When specified, the config variable "core.sharedRepository" is set so that files and directories under $GIT_DIR are created with the requested permissions. When not specified, Git will use permissions reported by umask(2).

What mean the "(2)" for the umask? I see such variant of value (umask) exists for the --shared option. Is it the same?

The git help umask finds nothing.

This simply refers to the section 2 of manual pages:

man 2 umask

Pages are traditionally referred to using the notation "name(section)": for example, ftp(1). The same page name may appear in more than one section of the manual, such as when the names of system calls, user commands, or macro packages coincide. Examples are man(1) and man(7), or exit(2) and exit(3).

https://en.wikipedia.org/wiki/Man_page