Where can download the offline documentation for nRF5_SDK_for_Thread_and_Zigbee_v3.0.0?
Unfortunately only the nRF5 SDK's have offline documentation. You can find online documentation here.
Will update one after? In some places in China, logging on the nordic official website to view the zigbee data network is very slow and inefficient.
This is not on the roadmap at the moment. You can ask your RSM about future road maps.