http://en.cppreference.com is a website hosting a free (GDFL/CC-BY-SA) wiki that aims to provide a C++ Standard Library reference. This package contains an archived version of that wiki, packaged into a Devhelp book. It would be good idea to have it in the official Ubuntu repositories, especially since there are no similar books there yet.
The upstream source tarball is at http://en.cppreference.com/w/Cppreference:Archives
I've already made a preliminary package in a PPA at https://launchpad.net/~p12/+archive/ppa . There might be some minor issues with license/copyright information since I don't have a lot of experience with Debian packaging and thus don't know where to put what. Apart from that, importing that package should need only minimal effort.
The packaging information itself is maintained at a git repository at https://github.com/p12tic/cppreference-doc-debian .