Benchmarking atomic data for astrophysics: Fe XI

High-resolution spectroscopic observations of the solar corona and laboratory measurements are used to review all the line identifications for Fe xi, from the EUV to the visible. The results of the atomic structure and scattering calculations are presented elsewhere, while detailed comparisons between observed and predicted wavelengths and intensities are discussed here. All the brightest EUV lines in the solar corona are now finally firmly identified. Several new identifications are proposed, in particular, coronal forbidden lines. The previously-known density-diagnostics are confirmed. New and important temperature diagnostics are presented, and the presence of blends highlighted.