What we know is that China possesses the capability to manufacture and design broadband anti-radiation missile seekers. In the game, Gaijin has also added Chinese anti-radiation missiles equipped with broadband seekers (CM-102, LD-10). However, Gaijin has not added a YJ-91 upgraded with a broadband seeker to the Chinese tech tree, which is unreasonable.
The Chinese Air Force still uses the YJ-91 as its primary anti-radiation munition to this day. It is not an abandoned munition that cannot be upgraded. Moreover, such an upgrade would not cost much, nor would it result in a noticeable difference in appearance.
From a general rational perspective, it is highly probable that the Chinese Air Force has updated and upgraded the seeker of the YJ-91. Advanced fighter jets such as the J-10C and the J-15T should be equipped with a seeker-upgraded YJ-91A, similar to the Kh-31PD.
At the same time, demanding credible internal documents on this topic is quite absurd. China’s management of such materials is extremely strict. Moreover, whether the performance of an anti-radiation missile’s seeker (such as frequency bands, frequency-hopping capability, anti-jamming ability, and tracking modes) remains classified or not directly affects the missile’s combat effectiveness. Under the premise that such materials are completely inaccessible in a safe manner, it is reasonable to infer the performance based on general reasoning — especially since Gaijin is already doing something similar in the game, such as allowing the Su-30MKM to use the Kh-38, which Malaysia never actually purchased.