China offered to provide microelectronics and other components and machine tooling for Russian industry in the very early days of the war. They've also been very important in providing finance, although they extract a lot of concessions for that. They also provide advice and engage with the Russian military in that way. There's ongoing joint training, I believe.
What we haven't yet seen is whether the Chinese will set up production in Russia, building factories in Russia and moving personnel and technicians to run them. That is a major risk. I think that is much more likely than directly supplying munitions, because the Chinese want to appear to be uninvolved. Nonetheless, their position is supportive of Russia, even if it's at arm's length.