Description of problem:
I found "dnf remove --duplicates" and "dnf remove --oldinstallonly" documented at http://dnf.readthedocs.io/en/latest/cli_vs_yum.html . But I didn't find it in "man dnf". Please include it, I needed it recently and spent some time searching the man pages to no avail.
Version-Release number of selected component (if applicable):
Fixed in dnf-2.0.0-0.rc1.