zulip/web/templates/settings/group_setting_value_pill_input.hbs

<div class="input-group">
    <label class="group-setting-label">
        {{label}}
        {{#if label_parens_text}}(<i>{{label_parens_text}}</i>){{/if}}
    </label>
    <div class="pill-container person_picker prop-element" id="{{#if prefix}}{{prefix}}{{else}}id_{{/if}}{{setting_name}}" data-setting-widget-type="group-setting-type">
        <div class="input" contenteditable="true" data-placeholder="{{t 'Add roles, groups or users' }}">
            {{~! Squash whitespace so that placeholder is displayed when empty. ~}}
        </div>
    </div>
</div>