He means it is unlikely that China has always sold top shelf and equal to PLA weapons except things like tanks or low level technology weapons which include things like tanks and artillery. Those being equal or higher than PLA own use is fine.
For aircraft and missile systems nearly always downgraded or totally different export model. In the past, Pakistan was very close with the US and no way to tell if there are any compromised people. Just takes one guy to leak and that's it.
Nowadays the risk is the same. Maybe everyone is fine except one person. Most strategic weapons and high tech systems are totally not for sale and many are not revealed at all.
Tengyun and other hypersonic reusable aircraft have been flying since 2018 in tests and only 2021 they admit they already can land it after some long duration flights.
These already are not fresh and newest developments. The combined cycle engines and special scramjet engines which are not conventional scramjets were leaked in 2018 and breakthrough after breakthrough mentioned. Only this year they showed some engine test photos and with blur of tests back in 2018 or before.
China is not like India in a comfortable position where if they don't touch China, China ignores them. If China leaks too much, US determines everything and can start developing counters but if leak too little, US feels too confident about war. So in recent years since tension increased with US, more leaks are granted.
Even weapons like J-20 is not for export. If everything is accessible then the J-20 would be too for PAF. As for something like missiles, well PL-15 is not top shelf sensitive missile and depending on needs assessment for PAF done by both partner countries, I think it is considered whatever version Pakistan buys is good enough. It is roughly same range as Meteor and possibly many times cheaper to buy for Pakistan. For every 10 Meteor India can buy, Pakistan for the same money probably can get 50 from China.
