Install the manpages-dev and manpages-posix-dev (thanks ChristopheD) packages. You should be able to find them in synaptic, or type apt-get install manpages- ...
Man pages are grouped into sections. To see the full list of Linux man pages for a section, pick one of: Section 1: user commands (introduction); Section 2 ... Introduction to user commands · Introduction to system calls
This page describes the conventions that should be employed when writing man pages for the Linux man-pages project, which documents the user-space API provided ...
This page is part of the man-pages (Linux kernel and C library user-space interface documentation) project. Information about the project can be found at ... Fcntl(2) · Read(2) · Write(2) · Openat2(2)