Variable: font-encoding-charset-alist

Alist of charsets vs the charsets to determine the preferred font encoding.
Each element looks like (CHARSET . ENCODING-CHARSET),
where ENCODING-CHARSET is a charset registered in the variable
`font-encoding-alist' as ENCODING.

When a text has a property `charset' and the value is CHARSET, a font
whose encoding corresponds to ENCODING-CHARSET is preferred.