I'll apologize in advance if this question has already come up and was solved:
We've uploaded a zip file containing an XLS workbook (multiple sheets within the workbook), and AGOL identifies the item as a "CSV Collection". When the item is then shared to the Open Data group it is not searchable through the provided search tool and only appears when you switch the view to "Items" when already looking at the full listing of data.

Is there any way to make this item searchable similar to other data items?