Mouseover the JSON key to see a brief description of each key. Keys that either haven't been identified (or that we haven't gotten around to adding yet) will show 'XXX'. Keys that are light gray are obsolete/legacy but still are returned in API responses.
Attachments can be added to, and downloaded from, to jobs both through the web UI or via the API. As far as I'm aware the attachment endpoints are some of the things only accessible using APIv3 and as such they're not covered in this document. Other than the obvious use of uploading and downloading attachments we've used the attachment endpoints to make attachments accessible from custom templates directly or using the data from them to manipulate a job. That being said, there's a lot that remains unexplored with them.
If you spot a mistake or know the purpose of an undescribed key please let us know by emailing kickservapi@veildg.com.