POSIX is the (more or less) standard all Unixes orient on. It describes libraries to use as well as binaries every Unix should have (like cp, mv) and their behaviour. You can find the standard on the Internet. Your task is to look for any non-trivial manpage (i.e., more than a few options) and research whether the NetBSD behaviour of this tool or library conforms to POSIX or not.
You should then insert this part into a list and document whether it complies to POSIX and if not, which differences are there.

As it is hard to determine the difficulty of a single part of the standard, this will be measured in lines. For every 1000 lines of the NetBSD versions of the manpages, this is one task.
The prerequisite is only for looking at libraries.

This task can be done multiple times and will be recreated once it's claimed.