Starting with the publication of Riemann's Gesammelte Mathematische Werke in 1876, the Commentatio Mathematica has attracted considerable interest among mathematicians and historians. Nonetheless, there appears to be no consensus on the most appropriate approach to the interpretation of the paper, namely on its relationship with Riemann's Habilitationsvortrag. This article represents a contribution to such an interesting debate. Special attention is paid to the pars secunda of Riemann's Commentatio. In particular, the focus is on the interpretation of a certain trinomial expression from which Riemann claimed that an understanding of his “curvature tensor” could be achieved.