The last column is the repository the package is coming from.
You can run the following command to get more info about a particular package:
[xxx@wasteland ~]$ dnf info zypp-common
Name : zypp-common
Version : 17.14.0
Release : 1.fc31
Architecture : noarch
Size : 486 k
Source : libzypp-17.14.0-1.fc31.src.rpm
Repository : fedora
Summary : Common files for ZYpp
URL : https://en.opensuse.org/Portal:Libzypp
License : GPLv2+
Description : This package provides the common files expected by libzypp
: and its consumers.
The updates repository exists for Branched and stable releases, but is only populated and used for stable releases. It is represented for Yum or [DNF](http://dnf.baseurl.org/) in the fedora-updates.repo file in the repository path. It exists in Branched releases solely to prevent various tools that expect its existence from breaking. For any Fedora installation, this repository will be enabled by default, and should usually remain so.