The low-temperature ⁵⁷Fe Mossbauer spectra of superconducting samples of Fe-substituted YBa₂Cu₃O_{7- delta} containing less than approximately 5 at.% Fe are characterized by a broad magnetically split profile. Although there is consensus in the literature as to the shape of this spectrum, there is no consensus of interpretation. Comparison of the fits obtained for two samples with 1% Fe substitution using (i) a hyperfine-field distribution model and (ii) a dynamic relaxation model demonstrates that the distribution model is marginally better, but that the relaxation model cannot be reliably discounted on the basis of the low-temperature Mossbauer data alone.