The source code clearly conveys the idea documented in SAP help: “When an offline store is first opened, it synchronizes with the OData producer. OData requests made against this plugin use the available open offline stores.“.
And I am curious how this offline store is opened in the real application. So I use a CRM Fiori offline application to have a look.
(1) In offline project folder there is a config.xml, which defines the entry point for offline application access, the index.html file.