char-property-alias-alistchar-property-alias-alist is a variable defined in `
C source code'. Its value is
nilDocumentation: Alist of alternative properties for properties without a value. Each element should look like (PROPERTY ALTERNATIVE1 ALTERNATIVE2...). If a piece of text has no direct value for a particular property, then this alist is consulted. If that property appears in the alist, then the first non-nil value from the associated alternative properties is returned.