I am using AEM 6.3. I am trying to understand the relationship between template policies (i.e. policy_123456) and the configuration stored in etc/design/<your-project-name>/.content.xml.
In [template]/policies, you can store mappings (sling:resourceType="wcm/core/components/policies/mapping") which sets the cq:policy value.* They map to policy_xxxxx nodes (sling:resourceType="wcm/core/components/policy/policy"), often (if not always) stored in /apps/settings/wcm/policies. And those policies store things like (allowed) "components", the "columns" used in a responsive grid, and so forth.
But there is also storing configurations in etc/design/<your-project-name>/.content.xml, according to Configuring Layout and Layout Mode. It's not clear if that information is to be stored directly in the <your-project-name> node, the <your-project-name> jcr:content node, or at <your-project-name> jcr:content > mycontentpath > myparsys. But it looks like "components" and "column" information can be stored there.
So my question is - which configurations get used under what circumstances? What is the hierarchy?
* side note - when templates are using the [template]/policies to get which components are allowed, Touch UI looks for policy mappings in a structure that matches the template, such as policies > jcr:content > mycontentpath > [myparsys mapping], whereas Classic UI looks for policy mappings right under jcr:content, such as jcr:content > [myparsys mapping].)