Perhaps I have explained myself wrongly, the Soviet era plans were the state's intellectual property and the drawings were archived in Moscow, any Soviet era "plans" automatically passed to the state that officially succeeded them, that is, the Russian Federation;
the military equipment of the USSR military apparatus is different and with agreements it has been divided with the nations born from the dissolution of the USSR.
Then certainly the design offices and military factories in the Soviet republics remained the property of the independent states.
In summary, all the projects carried out in the Soviet era, intellectual property is available to Moscow, even if materially at that time it was designed in offices located in Ukraine or other republics of the USSR, if then the Ukrainians sold a prototype that remained their disposal, this does not automatically grant the license to replicate it to whoever bought it.
Ok. I'm absolutely at a loss. Are we saying all military items, from hardware to design belongs to Russia. And the former states like Ukraine have no rights to these, even if they own and have the hardware! As such they got no rights to sell the T10. And any work subsequently on it is illegal?! Surly this applies to the Varig too!
But as others have mentioned. That the subsequent Ukrainian engineers working in China. That's legal right? So China developing the J15 is legitimate. Right? They didn't reverse engineer anything as they didn't have the SU33 to reverse engineer from the first place.
So the only thing that's wrong is the purchase of the T10 because it didn't belong to the Ukrainians?!