I think what happened is Missouri + 16 filed in support of Texas. This simply means they filed a brief as a friend to the court, giving their guidance on why the court should hear this case. Then, a subset of that group also wanted to be a party to the complaint itself. I think 10 states said, OK we will support, but we do not want to be a party. That is why they filed a second motion Missouri+6 to intervene.
Thanks, but I am asking about the first entry on the chart, is that the Gov of MO, being opposed?