While using the Maven Deployment Linker, and not otherwise storing build artifacts locally, "Maven Deployments" are listed for every build as links to your Maven Repository (e.g.: Artifactory). But there is no corresponding data retrieved while using the Remote Access API (JSON or XML). For example, if you had a link similar to this:

http://<hostname>/jenkins/job/<jobname>/<buildnumber>/

You'll see a list of build artifacts deployed to your Maven Repo. But when hitting the Remote Access API like this:

http://<hostname>/jenkins/job/<jobname>/<buildnumber>/api/json?pretty=true

You end up with:

"mavenArtifacts" : null,