  The composition of relativistic outflows producing gamma-ray bursts is a long
standing open question. One of the main arguments in favor of magnetically
dominated outflows is the absence of photospheric component in their broadband
time resolved spectra, with such notable example as GRB 080916C. Here, we
perform a time-resolved analysis of this burst and confirm the previous
detection of an additional spectral component. We show that this subdominant
component is consistent with the photosphere of ultrarelativistic baryonic
outflow, deep in the coasting regime. We argue that, contrary to previous
statements, the magnetic dominance of the outflow is not required for the
interpretation of this GRB. Moreover, simultaneous detection of high energy
emission in its prompt phase requires departure from a one-zone emission model.
