The next release of virt-manager will not ship the virt-convert tool, I removed it upstream with this commit.

Here's the slightly edited quote from my original proposal to remove it:

virt-convert takes an ovf/ova or vmx file and spits out libvirt XML. It started as a code drop a long time ago that could translate back and forth between vmx, ovf, and virt-image, a long dead appliance format. In 2014 I changed virt-convert to do vmx -> libvirt and ovf -> libvirt which was a CLI breaking change, but I never heard a peep of a complaint. It doesn't do a particularly thorough job at its intended goal, I've seen 2-3 bug reports in the past 5 years and generally it doesn't seem to have any users. Let's kill it. If anyone has the desire to keep it alive it could live as a separate project that's a wrapper around virt-install but there's no compelling reason to keep it in virt-manager.git IMO

That mostly sums it up. If there's any users of virt-convert out there, you likely can get similar results by extracting the relevant disk image from the .vmx or .ovf config, pass it to virt-manager or virt-install, and let those tools fill in the defaults. In truth that's about all virt-convert did in to begin with.

Please see virt-v2v for an actively maintained tool that can covert OVA/OVF appliances to libvirt + KVM. This article describes an example conversion.