The Kharkov plant is where it was originally produced the T80?
Is the Kharkov plant still operative? Does Ukraine produce anything there?
The Kharkov plant was where the T-34, T-64, and T-80 were designed. The T-80 was produced in variants with the opposing piston diesel engine there as well. After the Soviet collapse they exported the T-80UD to Pakistan and designed the T-84 Oplot. The Kharkov plant mostly refurbishes T-64 tanks for Ukraine today. But I doubt it has much output given that it is close to the border with Russia and can be easily bombed.
Nizhny Tagil designed the T-54, T-62, T-72, T-90, T-14 tanks. Today they make the T-90M (new and upgraded) and T-72B3M (upgraded).
The gas turbine variant of the T-80 was designed and produced at Omsk. The Omsk plant also produces the chassis for the Msta-S artillery. They had a project for a modernized T-80 with an extra pair of roadwheels in the 1990s called the "Black Eagle" but it got cancelled. Today they make the T-80BVM tank upgrade and are ramping up to make whole new tanks.
The Leningrad plant used to be where heavy tanks were designed. They developed the KV-1, IS-2, and T-10. But it was closed down with the Soviet collapse. I think they make agricultural tractors today.