As per sources that
@Ashwin found, it's apparently a nuclear version of the 039 Song-class SSK.
041 is the designation of the type.
Unclear to me what's the purpose of such a small SSN considering China already builds larger, more capable nuclear boats like the continously-updated 093 family. Perhaps they thought a smaller, cheaper boat that can be produced in larger numbers is more ideal for littoral operations within the first island chain.
Or perhaps it's aimed as an export option for Chinese client states like Pakistan (to counter India's upcoming SSNs) or even Indonesia (if they end up becoming too uncomfortable with Australia having SSNs). With AUKUS going through, there's not much to point fingers at China if they too start exporting SSNs.