Matter of fact

"The introduction of a universal basic income is, he believes, inevitable. This drastic reinvention of the welfare state would see the government pay every single citizen, irrespective of their wealth or employment status, a regular cash sum calculated to cover all their basic needs. The only country in the world to experiment with the policy so far is Finland, but Peston sounds almost nonchalantly matter of fact when he predicts, as if stating the obvious: “We will end up with it. We just have to reconcile ourselves to no growth." (The Guardian.)

Is "matter of fact" an adjective in the passage above?