... Since users won't expect to be asked to select their subdivision for a shipping address in some countries that don't use them for mailing, I expect that in Firefox we won't show a subdivision field and therefore won't populate the region or regionCode fields for those countries such as Belgium, Germany, etc. Perhaps the spec and/or MDN should be more clear that an empty string can be valid for mailing purposes.
In https://github.com/w3c/contact-picker/issues/65 @mnoorenberghe wrote:
Should add a note to the spec as per above👆