In this post, ROS and Gazebo Answers Migration to Robotics Stack Exchange Process
you can read:
Unfortunately, we can’t transition all ROS Answers content, and it will not be perfect. However, we plan to be transparent about what’s happening, and respond to community feedback about the process.
I thought there was an even more detailed description of what will be migrated, but I couldn’t quickly find it… I think it was something about questions with no answers, comments and votes not being migrated.