```
@Documented
@Retention(RUNTIME)
@Target({TYPE_USE,TYPE_PARAMETER})
@TargetLocations(ALL)
@InvisibleQualifier
@SubtypeOf({})
@DefaultQualifierInHierarchy
public @interface I18nUnknownFormat
```
The top qualifier.
A type annotation indicating that the run-time value might or might not be a valid i18n format string.
It is usually not necessary to write this annotation in source code. It is an implementation detail of the checker.

See the Checker Framework Manual:
Internationalization Format String Checker

Annotation Type I18nUnknownFormat