anchor.diff:  When a job runs on an agent, the first combination of environment variables happens in the job environment itself. This is the environment you can see in a job’s Environment tab in the Buildkite dashboard, and the one returned by the REST and GraphQL APIs.
   
   <div class="Docs__note">
  -  <p>The precedence of environment variables is different from what's listed here if you are using <a href="https://buildkite.com/changelog/32-defining-pipeline-build-steps-with-yaml">YAML Pipeline Steps (beta)</a>.</p>
  -  <p>For more information, please consult <a href="https://forum.buildkite.community/t/changes-to-environment-variable-precedence/107">our Community Forum post about the YAML Pipeline Steps beta</a>.</p>
  +  <p>If you are not using YAML Steps, the precedence of environment variables is different from the list below.</p>
  +  <p>Please <a href="/docs/tutorials/yaml-pipeline-upgrade">migrate your pipelines</a> to use YAML steps. See the <a href="/docs/tutorials/yaml-pipeline-upgrade">deprecation notice</a> for more information.</p>
   </div>
   
   The job environment is made by merging the following sets of values, where values in each successive set take precedence:
  
positive.code:       <td><code>MY_ENV1="a"</code></td>
      </tr>
      <tr>
        <th><em>Step</em></th>
        <td><code>MY_ENV1="b"</code></td>
      </tr>
      <tr>
        <th><em>Build</em></th>
        <td><code>MY_ENV1="c"</code></td>
      </tr>
    </tbody>
  
negative.code:     <td>Optional variables set by you on a pipeline on the Pipeline Settings page</td>
    </tr>
    <tr>
      <th><em>Build</em></th>
      <td>Optional variables set by you on the build when creating a new build in the UI or via the REST API</td>
    </tr>
      <tr>
      <th><em>Step</em></th>
      <td>Optional variables set by you on a step in the YAML steps editor or a pipeline.yml file</td>
    </tr>
    <tr>
      <th><em>Standard</em></th>
  