API responses for builds return include "actions" arrays, which are now containing both objects and arrays as elements. Prior to 2.0 this was not the case. E.g:

{
"actions" : [
{

},
[

],
{
"causes" : [

{ "shortDescription" : "Started by upstream project \"authy_master\" build number 120", "upstreamBuild" : 120, "upstreamProject" : "authy_master", "upstreamUrl" : "job/authy_master/" }

]
},
{

},
...

Note the second element there is an empty array. Is this WAD? Returning JSON in such a format makes response parsing much more difficult.