chrome/browser/resources/about_sys/app.html

<if expr="is_chromeos">
    <link rel="stylesheet" href="chrome://resources/css/os_header.css">
</if>

<if expr="is_chromeos">
    <!--
      For Ash, we need to use the JavaScript handler to open the system page
      in Lacros. For Lacros we can use href="os://system" instead.
    -->
    <div class="os-link-container-container"
<if expr="chromeos_ash">
        ?hidden="${!this.isLacrosEnabled_}"
        @click="${this.onOsLinkContainerClick_}"
        @auxclick="${this.onOsLinkContainerAuxClick_}"
</if>
    >
      <div class="os-link-container">
        <span class="os-link-icon"></span>
        <!-- This includes an <a> tag with id='osLinkHref'. -->
        $i18nRaw{osLinkContainer}
      </div>
    </div>
</if>

<div id="header">
  <h1 id="title">$i18n{title}</h1>
  <p>$i18n{description}</p>
</div>

<key-value-pair-viewer ?loading="${this.loading_}" .entries="${this.entries_}">
</key-value-pair-viewer>