The correspondences given in iso0[1-9].sfm are
according to The Unicode Standard, Version 1.0, Vol. 1.

Most of the remaining ones are phantasy.

`ethiopic.sfm' is the one used by the `Agafari', `Goha', and `GohaClassic' fonts.

`def.sfm' is the default one, used by the kernel on boot (codepage 437).

`cp437.sfm' is basically quite similar with `def.sfm', but has some
approximations defined, and a few mappings are a bit different.
