The modes file collects all known Metafont modes for printing
or display devices, of whatever printing technology. Special
provision is made for write-white printers, and a 'landscape'
mode is available, for making suitable fonts for printers with
pixels whose aspect is non-square. The file also provides
definitions that make \specials identifying the mode in
Metafont's GF output, and put coding information and other
Xerox-world information in the TFM file.