We are talking about J-16 combat aircraft, which are an exact copy of the Soviet MiG-19. These are the same fighters that China has been producing under the license of the USSR since the mid-50s of the XX century.
The last J-16s were decommissioned about 11 years ago. But Chinese experts have found a use for them in our time, turning them into UAVs.
Interestingly, for the first time reports of such a “rebirth” began to appear back in 2013. Then it was said that the aircraft were also used as decoys to mislead the enemy’s air defense.
Note that the USA has chosen a similar path for themselves. US Air Force specialists have developed their own QF-16 attack drone based on the outdated F-16 fighter.