[NOEMAOFFLINE\]LIST [Spw1 Spw2] [/CONFLICT] [/INDEX]
List the defined spectral windows. If present Spw1 and Spw2 define the
range of listed spectral windows. They are sorted according to resolu-
tion (low resolution first), then RF frequency and finally polarization
(order different from the index one, which follows the true order at the
observatory)