The wave function statistics at the Anderson transition in a two-dimensional disordered electron gas with spin-orbit coupling is studied numerically. In addition to highly accurate exponents (α0=2.172±0.002,τ2=1.642±0.004), we report three qualitative results. (i) The anomalous dimensions are invariant under q→(1−q) which is in agreement with a recent analytical prediction and supports the universality hypothesis. (ii) The multifractal spectrum is not parabolic and therefore differs from behavior suspected, e.g., for (integer) quantum Hall transitions in a fundamental way. (iii) The critical fixed point satisfies conformal invariance.