According to the documentation and source code a .json-file should be saved with the requested variables. I set it to be stored in the default folder (Build.ArtifactStagingDirectory), but I don't see it in the final result of my build step. I am publishing build artifacts from the mentioned folder, but no .json files appear. I am using Azure DevOps Server. See the attached screenshot for the logs:

According to the documentation, the last log line should log "created {result}", but it just logs "created ".