Last time I checked their iOS app pinged the backend around every 10 seconds for a big ol' payload of JSON config etc, which contained most of the A/B stuff and

Last time I checked their iOS app pinged the backend around every 10 seconds for a big ol' payload of JSON config etc, which contained most of the A/B stuff and UI config (which car types to display, e.g., as where you are they might not have all of X/taxi/Black/Lux etc).