When install Fedora Robotics in virtualbox 7.0.10， after start Fedora Robotics， top left corner is a white cube， then install into disk，chinese version， reboot again，top left corner is a white cube as before。

Yes, GNOME changed it. It no longer says Activities, it shows workspaces. The active one is a white bar, the inactive ones are grey dots. You can see it e.g. in this video: https://www.youtube.com/watch?v=47aZgF6xmS0

I also thought it was a bug, initially :-)