The upstream manpages author decided to include GNU utils non-official manpages here, as the FSF doesn't want to maintain them. I agree with him, but these manpages should be added to the corresponding Debian package of the GNU utilities, not here. Having manpages is very important to every operating system. It is much work to keep those documents up to date and to initially write them. Nevertheless some folks made some of this work.
Contributions are welcome.