Looking at the code, I'd be surprised if the markup did not exist and was not just having styles overridden. Can anyone produce attachment the output as HTML of a part of the log (redacted if necessary)? should be as simple as selecting with mouse, right-click and "copy as HTML". This way we can know if it's failing to parse the text or if it's a front-end glitch.

Lewis Cowles it appears to be a front-end issue. I picked a random output line from a Chef command which appears green in the legacy UX but is indistinguishable from the rest of the output in Blue Ocean:

Jenkins Console Output:

<span style="color: #00CD00;">- restart service service[httpd]</span>

Jenkins Blue Ocean Console Output

<tr id="step-134-log-524">
  <td class="linenumber">
    <a href="#step-134-log-524" name="step-134-log-524">524</a>
    <!-- react-text: 4068 --> 
    <!-- /react-text -->
  </td>
  <td class="line"> - restart service service[httpd]</td>
</tr>

If I manually add the inline style to the td with class="line" it overrides the styling from this .line class and works. There might need to be an update made to the plugin however, because I don't see any reference to the green style in the CSS hierarchy for the <tr> node at all.

Looking at this, I'm not sure it is a front-end issue. Forcing inline style changes is probably not the way forward the specific td needs a style tag appended to it by the looks of things.

Lewis Cowles I think you will find we have to add an extension point in blueocean-rest-impl for the ansi color plugin to pass that color info up into the response and then some sort of decorator extension point in the JS

It is likely that we would like to support ANSI Color right out of the box with JENKINS-41200.