What is that fixture called as? I think it is used to support the launch vehicle during integration. Please correct if wrong.
source - https://www.ruaviation.com/news/2019/3/12/13107/?h
here's another one showing many such structures.
source - https://spaceflightnow.com/2021/01/10/china-to-begin-construction-of-space-station-this-year/