This plugin shows in the UI some icons (with different sizes) to indicate actions. These icons are broken because its URL is wrong. i.e.

/**
 * {@inheritDoc}
 */
public String getIconFileName() {
    return isDeployPossible(owner) ? Jenkins.RESOURCE_PATH
            + "/plugin/cloudbees-deployer-plugin/images/24x24/deploy-now.png" : null;
}

Why is wrong? Because the short-name of this plugin is deployer-framework not cloudbees-deployer-plugin.