Pass ?urls= as a URL-encoded JSON array of catalog detail URLs. Each URL is mapped to a source; if the same source appears more than once, the last wins. With no usable URLs, the matrix stays empty. A single column adds cross-source Google search (from resolve searchable) in the sidebar.
No catalog URLs yet. Open this page with ?urls= set to a JSON array (e.g. from movie search or the cross-source sidebar after resolving a single film).