refactor(location-field): Add comments for a11y requirements and assu…

…mptions.

packages/location-field/src/index.tsx

@@ -195,8 +195,10 @@ const LocationField = ({
     return location && !hideExistingValue ? label : "";
   };
 
+  // FIXME: This class name seems only used in OTP-RR for Percy tests to identify the component.
   const formControlClassname = `${locationType}-form-control`;
 
+  // We assume there is only up to one location field component for each value in LocationType.
   const listBoxId = `${locationType}-listbox`;
 
   const intl = useIntl();
@@ -936,6 +938,8 @@ const LocationField = ({
           value={statusMessages}
         />
       </S.HiddenContent>
+      {/* The results list is always in the DOM (but hidden in desktop if no results are shown),
+          so that assistive technology can associate the list with the button and input controls. */}
       <ItemList
         aria-label={intl.formatMessage({
           defaultMessage: "Suggested locations",