Fedora has changed the default package manager from yum to dnf
From Fedora 22, dnf is now the default package manager (https://fedoraproject.org/wiki/Changes/ReplaceYumWithDNF). The attached patch reflects this.
I'm uncertain if its 100% necessary to do this yet, as using yum to install a package will direct the user to the dnf command but Fedora 22 was released in May 15 so I imagine the majority of users will have upgraded.
Trac:
Username: icanhasaccount