GitCode, a git-hosting website operated Chongqing Open-Source Co-Creation Technology Co Ltd and with technical support from CSDN and Huawei Cloud.
It is being reported that many users’ repository are being cloned and re-hosted on GitCode without explicit authorization.
There is also a thread on Ycombinator (archived link)
I do believe it’s illegal if they take a repository with a restrictive license (which includes any repository without a license), and then make it available on their own service. I think China just doesn’t care.