As the developer and provider of xIFr, I have no interest in or intent to collect data about users or usage of xIFr, besides the basic add-on statistics automatically logged by Mozilla Add-ons Store. In general xIFr ain't running until either launched from context-menu or by opening addon's Option page, and no data is processed, collected or shared unless needed for the addon's described functionality.
xIFr reads and presents data about image files embedded on webpages, and does so no matter if an image file is located on same domain as the webpage itself or embedded from some other domain. To show position of geotagged photos, xIFr will embed a map from - and communicate geolocation data to - a 3rd party map-provider (Currently OpenStreetMap). But besides the needed data shared to show a map with photo location, xIFr does not share any data with 3rd parties. And there's no communication with the map-provider until the "Map" tab in xIFr is selected for a geotagged photo.