RHEL Engineering is moving the tracking of its product development work on RHEL 6 through RHEL 9 to Red Hat Jira (issues.redhat.com). If you're a Red Hat customer, please continue to file support cases via the Red Hat customer portal. If you're not, please head to the "RHEL project" in Red Hat Jira and file new tickets here. Individual Bugzilla bugs in the statuses "NEW", "ASSIGNED", and "POST" are being migrated throughout September 2023. Bugs of Red Hat partners with an assigned Engineering Partner Manager (EPM) are migrated in late September as per pre-agreed dates. Bugs against components "kernel", "kernel-rt", and "kpatch" are only migrated if still in "NEW" or "ASSIGNED". If you cannot log in to RH Jira, please consult article #7032570. That failing, please send an e-mail to the RH Jira admins at rh-issues@redhat.com to troubleshoot your issue as a user management inquiry. The email creates a ServiceNow ticket with Red Hat. Individual Bugzilla bugs that are migrated will be moved to status "CLOSED", resolution "MIGRATED", and set with "MigratedToJIRA" in "Keywords". The link to the successor Jira issue will be found under "Links", have a little "two-footprint" icon next to it, and direct you to the "RHEL project" in Red Hat Jira (issue links are of type "https://issues.redhat.com/browse/RHEL-XXXX", where "X" is a digit). This same link will be available in a blue banner at the top of the page informing you that that bug has been migrated.

Description of problem:
Currently it seems to me there's no way to get the package vendor through the dnf API. To provide feature parity of both yum and dnf, please add a vendor property to the Package class (https://dnf.readthedocs.io/en/latest/api_package.html#dnf.package.Package). In yum, it is available in the RPMInstalledPackage class.

Version-Release number of selected component (if applicable):
dnf-0:4.2.17-6.el8.noarch
rpm-0:4.14.2-37.el8.x86_64

Steps to Reproduce:
RHEL 7.8:
```
import yum
yum_base = yum.YumBase()
print(yum_base.rpmdb.returnPackages()[0].vendor)
```
Output: 'Red Hat, Inc.'

RHEL 8.2
```
import dnf
dnf_base = dnf.Base()
dnf_base.fill_sack(load_system_repo=True, load_available_repos=False)
dnf_base.sack.query().installed()[0].vendor
```
Output: Traceback "AttributeError: 'Package' object has no attribute 'vendor'"

Actual results:
I'm unable to get the vendor of a package through the dnf python module.

Expected results:
I have a way to get the vendor of a package through the dnf python API.

As a workaround, in Convert2RHEL we started printing a packager instead of a vendor of a package. However, Oracle Linux packages have the packager field empty. They have just the vendor field filled in ("Oracle America"). Because of that, the output of Convert2RHEL is quite confusing:
```
WARNING - The following packages will be removed...
Package                                     Packager  Repository
-------                                     --------  ----------
oraclelinux-release-8:8.2-1.0.8.el8.x86_64  N/A       N/A
```

I made two PRs to address the issue.

dnf: https://github.com/rpm-software-management/dnf/pull/1677
libdnf: https://github.com/rpm-software-management/libdnf/pull/1073

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (dnf bug fix and enhancement update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2021:1657