Accessing the data in a feature service layer

joepublic

I am a newbie with esri and have a basic question. 

I have the the following ESRI feature service: http://dev.consciousglobalchange.org/arcgis/rest/services/MEP/noRelate_tester/FeatureServer/0

How do I find the key/value of the data that I want to display in a popup

 

var popupTemp = ???

countries.bindPopup(function(feature) {

return L.Util.template(popupTemp, feature.propeties)

});