In my Nuvi 2597, I have USA Maps City Navigator North America NT 2021.1 installed as default (I get the free updates) and I have recently downloaded and installed City Navigator Europe NTU 2020.2 - so both are in he unit memory, not via SD card.
When I view my folders and files, I have the following?
From Root Menu:
Folder - Garmin - Folder JVC (not JCV) - Contains D616504A and D621204A
Folder - ...