
Under Metrics & Segmentation in the X Ads API documentation the segmentation types list includes LOCATIONS (which covers country) — “Segmentation reporting allows the retrieval of metrics broken out by the values of a given targeting type.”
https://developer.x.com/en/docs/x-ads-api/analytics/overview/metrics-and-segmentation?

Segmentation fields were added:
https://windsor.ai/data-field/twitter/#age
https://windsor.ai/data-field/twitter/#app_store_category
https://windsor.ai/data-field/twitter/#audience_segment
https://windsor.ai/data-field/twitter/#conversation
https://windsor.ai/data-field/twitter/#conversion_tag
https://windsor.ai/data-field/twitter/#event
https://windsor.ai/data-field/twitter/#gender
https://windsor.ai/data-field/twitter/#interest
https://windsor.ai/data-field/twitter/#keyword
https://windsor.ai/data-field/twitter/#language
https://windsor.ai/data-field/twitter/#location
https://windsor.ai/data-field/twitter/#platform
https://windsor.ai/data-field/twitter/#similar_followers
https://windsor.ai/data-field/twitter/#slide
https://windsor.ai/data-field/twitter/#tv_show
