discourse/app/assets/javascripts/admin/templates/components/themes-list.hbs

<div class="themes-list-header">
  <div {{action "changeView" THEMES}} class="themes-tab tab {{if themesTabActive 'active' ''}}">
    {{d-icon "cube"}}
    {{I18n "admin.customize.theme.title"}}
  </div><div {{action "changeView" COMPONENTS}} class="components-tab tab {{if componentsTabActive 'active' ''}}">
    {{I18n "admin.customize.theme.components"}}
  </div>
</div>

<div class="themes-list-container">
  {{#if hasThemes}}
    {{#if hasActiveThemes}}
      {{#each activeThemes as |theme|}}
        {{themes-list-item theme=theme navigateToTheme=(action "navigateToTheme" theme)}}
      {{/each}}

      {{#if hasInactiveThemes}}
        <div class="themes-list-item inactive-indicator">
          <span class="empty">
            {{#if themesTabActive}}
              {{I18n "admin.customize.theme.inactive_themes"}}
            {{else}}
              {{I18n "admin.customize.theme.inactive_components"}}
            {{/if}}
          </span>
        </div>
      {{/if}}
    {{/if}}

    {{#if hasInactiveThemes}}
      {{#each inactiveThemes as |theme|}}
        {{themes-list-item theme=theme navigateToTheme=(action "navigateToTheme" theme)}}
      {{/each}}
    {{/if}}
  {{else}}
    <div class="themes-list-item">
      <span class="empty">{{I18n "admin.customize.theme.empty"}}</span>
    </div>
  {{/if}}
</div>