This plea is “I still proclaim innocence, but I agree that the State case is strong enough to convict me, and I do not have a sufficient defense.” Such a plea is allowed when the plea deal offers an escape from a more severe sentence, as in life in prison vs. capital punishment, making the plea “in the best interest” of the accused.

This sounds a lot like a “the state violated my right to a fair trial but I have no recourse” plea.