I noticed an empty comment block in JSONP output returned by facebook graph api for all methods.
URL that I called :
https://graph.facebook.com/NUMER
Could be some kind of seperator to have a fixed start. I guess Facebook had a reason to but it there but we can only guess and it does not really matter does it? :)
We added this to protect against an attack where a third party site bypasses the content-type of the response by doing:
<object type="application/x-shockwave-flash"
data="http://graph.facebook.com?callback=[specifically crafted flash bytes]">
</object>
Google does something similar, except they use //... + \n (e.g. http://www.google.com/calendar/feeds/developer-calendar@google.com/public/full?alt=json&callback=foo)