Dandified Yum (DNF) is the next upcoming major version of Yum. It does package management using RPM, libsolv and hawkey libraries. For metadata handling and package downloads it utilizes librepo. To process and effectively handle the comps data it uses libcomps.
DNF and all its dependencies are available in Fedora 18 and later, including the rawhide Fedora. You can install DNF from the distribution repositories there:
sudo yum install dnf
In other RPM-based distributions you need to build all the components from their sources.
From the DNF git checkout directory:
mkdir build; cd build; cmake .. && make;
Then to run DNF:
PYTHONPATH=`readlink -f .` bin/dnf <arguments>
The DNF package distribution contains man pages, dnf(8) and dnf.conf(8). It is also possible to read the DNF documentation online, the page includes API documentation. There's also a wiki meant for contributors to DNF and related projects.
Please report discovered bugs to the Red Hat bugzilla.
Freenode's irc channel #yum is meant for discussions related to both Yum and DNF. Questions should be asked there, issues discussed. Remember: #yum is not a support channel and prior research is expected from the questioner.