Details:
* The option `fonts.fontconfig.ultimate.enable` can be used to disable
the fontconfig-ultimate configuration.
* The user-configurable options provided by fontconfig-ultimate are
exposed in the NixOS module: `allowBitmaps` (default: true),
`allowType1` (default: false), `useEmbeddedBitmaps` (default: false),
`forceAutohint` (default: false), `renderMonoTTFAsBitmap` (default:
false).
* Upstream provides three substitution modes for substituting TrueType
fonts for Type 1 fonts (which do not render well). The default,
"free", substitutes free fonts for Type 1 fonts. The option "ms"
substitutions Microsoft fonts for Type 1 fonts. The option "combi"
uses a combination of Microsoft and free fonts. Substitutions can also
be disabled.
* All 21 of the Infinality rendering modes supported by fontconfig-ultimate
or by the original Infinality distribution can be selected through
`fonts.fontconfig.ultimate.rendering`. The default is the medium style
provided by fontconfig-ultimate. Any of the modes may be customized,
or Infinality rendering can be disabled entirely.
