API - Undocumented "include" value: "job.config"

Information such as job title is very important when analyzing results retrieved via the API, but that isn’t included by default. It isn’t mentioned in the API docs, but by reviewing the requests issued from travis-ci.org, I found that request for build/{build.id}?include=job.config will include that information.

Is this considered stable? Can the documentation be updated to describe it?