Hi vickyg28253246,
I didn't mention out of box variables. What I meant was the variables which are populated in the AppMeasurement implementation can be classified. While the variables which are automatically populated by Adobe can't be classified.
Variables like campaign, product, channel are populated using s.campaign, s.product, s.channel variable in the implementation. But we don't have any variable to populate Countries or Browser.
Does that help?
Thanks!