What mime type/format should I use to set the clipboard to allow pasting of data in Google Sheets?

Question

I have some tabular data within my Qt application. I would like users to be able to select this data and paste in Google Sheets (without having to 'import' the data). I am able to do this if I set MIME type to "text/plain" and MIME content to table values separated by TAB and using QClipboard->setMimeData(). But I want to use text/plain for another purpose. What MIME type can I use to populate the clipboard so as to support paste in Google Sheets? I have tried "text/csv", "application/csv" and "csv" to no avail. "csv" seems to work for Excel.