PdfViewerActivityParams
data class PdfViewerActivityParams(val cachedFileUri: String, val fileName: String, val source: BrowserScreens.PdfViewerSource) : GlobalActivityStarter.ActivityParams
Use this model to launch the standalone PDF viewer for a PDF at cachedFileUri, displaying fileName in the toolbar. Check com.duckduckgo.browser.api.pdf.PdfViewerAvailability before launching this screen.
source identifies where the open came from: it gates the external-open pixels (fired only for PdfViewerSource.EXTERNAL_INTENT) and the back-navigation target (external opens land in the browser, in-app opens return to the launching screen).