zulip/zephyr/jstemplates/narrowbar.html

<span id="currently_narrowed_to"
    title="{{description}}{{#if subject}}  |  {{subject}}{{/if}}">

    <i class="icon-{{icon}}"></i>
    {{description}}
    {{#if subject}}
    &nbsp; | &nbsp; {{subject}}
    {{/if}}
</span>