Filters the sanitization of a specific meta key of a specific meta type and subtype.

The dynamic portions of the hook name, $object_type, $meta_key,
and $object_subtype, refer to the metadata object type (comment, post, term, or user),
the meta key value, and the object subtype respectively.

return apply_filters( "sanitize_{$object_type}_meta_{$meta_key}_for_{$object_subtype}", $meta_value, $meta_key, $object_type, $object_subtype );