How open is China in sharing data from the Chang'e 4 mission? It's really good to see that man (well, machine) has gone back to the moon again.

Chang'e 4 is studying potential mantle material from the lunar depths and will be conducting radio astronomy in frequencies that simply aren't possible from Earth.

There's a huge amount to be learned that will fill some gaps in our knowledge of the early Moon, Earth, and the Solar system as well as the wider galaxy and beyond.

Will this information be open for the greater scientific community, or will we have to rely on the Chinese scientists to collate and publish the data as and when they can do?
Different space agencies and different governments have different policies about archiving their data.  One commonality that I have found, though, is that their systems are often difficult to find, they are often difficult to navigate or search and get the data, and then just as difficult sometimes to process.  Sometimes, they also require an account.
Doing an internet search for simply &quot;Chang'e 4 data archive&quot; linked me to this conference abstract as the first link, which was presented at the mid-2019 Data Users' Workshop in Flagstaff, AZ.  The abstract explains the different data types (such as level 0A, level 1, level 2C, etc.) and the different instruments, and it also explains their data archiving plan.
Perhaps more important for this question, it provides a link to China's &quot;Data Release and Information Service System&quot; within China's Lunar Exploration Program.
It has a lovely English translation button in the upper-left, so clicking on that (because I do not speak nor read any type of Chinese), and the news to the right shows they have Chang'e 4's 12th data release as their most recent posting.  You can follow through the links and find the data archived there, or, this is a direct link to the search engine.
Of course, as with any mission, agency, or government, you have to assume that they are publishing everything, but I see no specific reason to doubt that in this case.  Keep in mind, though, that there is always a waiting period between the time the data are taken and the time they are posted on public archives.  With NASA, that is usually 6 months, though at the start of mission data returns it can be more like 12 months.  So, just because data might not go up through today in these archives, that does not mean that they won't in 6–12 months.