Attributes provided in CSImportExtension are not searchable in Files.app or UIDocumentBrowserViewController

I created a CSImportExtension in my UIDocument-based app to make the content of my documents searchable. Now I can successfully search for the content from the iOS home-screen search. But when I try the same search in the Files.app or from the document browser in my app, no results are shown.

In the update attributes function in the extension, I am populating the following fields of the passed-in CSSearchableItemAttributeSet: keywords, contentDescription, displayName

Does anybody know what I have to do to make the content searchable from all locations? I tried the same within the Pages, Numbers and Keynote apps and their document contents is found beautifully from the Files.app or from their document browsers. So it seems to work in principle.

Thanks and cheers

Frank

Attributes provided in CSImportExtension are not searchable in Files.app or UIDocumentBrowserViewController
 
 
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