The combined stuff is available to components using the page store as $page.stuff, providing a mechanism for pages to pass data 'upward' to layouts.

You can also just throw<% yield :javascript_packs %>somewhere in your layout, and use<%= content_for :javascript_packs do %><%= javascript_pack_tag 'visitor' %><% end %>

I ran in to what I thought was this issue, but I was using fragment caching. Since the partial was not executed again, the content_for was not called. content_for could be written differently to handle this.