Hello,
The problem is, the data-template-name
should be unique name. Developer’s guide to Discourse Themes. Like this: data-template-name="/connectors/PLUGIN-OUTLET-NAME/UNIQUE-NAME"
Now you use the sidebar
name in your example which is I think override Fakebook sidebar template.
For example this should work
<script type="text/x-handlebars" data-template-name="/connectors/discovery-below/downloadlink">
<div class="top-navbar">
<span class="j_menu_item" ><a href="https://www.example.com/download">{{i18n (theme-prefix "top-navbar.download")}}</a></span>
</div>
</script>