Manafort is cooperating with Mueller
It's not yet clear how much cooperation he will be doing, or what he knows. He's certainly not getting a sweetheart deal. He's already been found guilty to counts that will lead to several years in jail and with this plea he will get more jailtime and has agreed to forfeit four bank accounts and give up all his property.
However on the Trump file, it's all about Trump about to put tariffs on China.