Why does Google prepend while(1); to their JSON responses?

Why does Google prepend while(1); to their JSON responses?

Why does Google prepend while(1); to their (private) JSON responses?
For example, here’s a response while turning a calendar on and off in Google Calendar:
while(1);[[‘u’,[[‘smsSentFlag’,’false’],[‘hideInvitations’,’false’],
[‘remindOnRespondedEventsOnly’,’true’],
[‘hideInvitations_remindOnRespondedEventsOnly’,’false_true’],
[‘Calendar ID stripped … Read more