I just downloaded a bunch of kepubs from
https://standardebooks.org/
The Standard Ebooks
guide says that I should copy these files straight on the Kobo, without using Calibre (they have a '.kepub.epub' extension).
However I do need to put these books on Calibre first - for practical reasons (library management/backup, etc.).
So I did try to add these ebooks to Calibre library, but the software detects them as simple epubs.
Is there a way to make Calibre read these files as kepubs in a native way, in order to avoid a new and unneeded conversion when I send them to the Kobo device?