I noticed that auto-layout frames now support wrapping items to the next line, which is really great to see 
Since users can now specify both vertical and horizontal item spacing values in wrapping auto-layout frames, this should be returned in API responses as well. Currently item spacing is represented as a single field, itemSpacing, which only takes into account spacing along the primary layout axis.
I propose adding a new field, counterAxisItemSpacing, or something similar, to represent spacing along the counter axis.
For the following example:
The JSON response could look like this:
itemSpacing: 10,
counterAxisItemSpacing: 35
As far as I know this would be a non-breaking change to the API.
Cheers and thanks again for adding wrapping to auto-layout frames!