I occasionally check trending repositories of chinse language in github https://github.com/trending?spoken_language_code=zh and github repositories of Alibaba, tencent etc. From the look of it they are very focused on tooling/tutorials on highly salable distributed systems architecture. Java is very popular and spring cloud is their preferred choice. One thing I found interesting is that hibernate ORM is not used anywhere, instead they prefer MyBatis data mapper framework. Some of those projects are moved to apache foundation.

On top of my head I found these projects interesting,

* Dolphin Scheduler https://github.com/apache/incubator-dolphinscheduler

* Echarts https://github.com/apache/incubator-echarts

* Ant Design https://ant.design/

* Sky walking APM https://github.com/apache/skywalking

* Seata distributed transaction system https://github.com/seata/seata

* EasyTransaction distributed transaction system https://github.com/QNJR-GROUP/EasyTransaction

* EShop-SOA https://github.com/songxinjianqwe/EShop-SOA

* RocketMQ https://github.com/apache/rocketmq

* Sharding Sphere https://github.com/apache/incubator-shardingsphere

* Jeecg-Boot https://github.com/zhangdaiscott/jeecg-boot

* SOFA Stack https://github.com/sofastack

* Dubbo RPC framework https://dubbo.apache.org/en-us/ . Also it seems that every big companies in China have their own RPC framework.