*** Defining fontsets.
Emacs does not use any fontset by default. Its default font is still
chosen as in previous versions. You can tell Emacs to use a fontset
with the `-fn' option or the `Font' X resource.
Emacs creates a standard fontset automatically according to the value of standard-fontset-spec. This fontset's short name is `fontset-standard'. Bold, italic, and bold-italic variants of the standard fontset are created automatically.
If you specify a default ASCII font with the `Font' resource or `-fn' argument, a fontset is generated from it. This works by replacing the FOUNDARY, FAMILY, ADD_STYLE, and AVERAGE_WIDTH fields of the font name with `*' then using this to specify a fontset. This fontset's short name is `fontset-startup'.
Emacs checks resources of the form Fontset-N where N is 0, 1, 2... The resource value should have this form: FONTSET-NAME, [CHARSET-NAME:FONT-NAME]... FONTSET-NAME should have the form of a standard X font name, except: