app/views/collections/show_published.html.erb
<%= render 'header', :collection => @collection %>
<%= render 'sidebar', :collection => @collection %>
<% if @new_collection_version.blank? && can?(:branch, @collection) %>
<div class="editing_versioning_toolbar">
<%= button_to t("txt.views.versioning.versioning_mode"),
collection_versions_branch_path(:origin => @collection.origin), :class => "btn btn-outline-secondary" %>
</div>
<% elsif can?(:read, @new_collection_version) %>
<div class="editing_versioning_toolbar">
<%= link_to t("txt.views.versioning.preview_new_version"),
collection_path(:published => 0, :id => @new_collection_version), :class => 'btn btn-outline-secondary' %>
</div>
<% end %>
<%= render 'data', :collection => @collection %>