It sounds like you're looking at a for Ace Combat 7: Skies Unknown Deluxe Edition . Before diving into a "guide," it's important to clarify a few things—because .XCI is a cartridge dump format used primarily with custom firmware (CFW) or emulators (like Ryujinx/Yuzu), not an official file you'd run on a stock Switch.
On other consoles, this is a hefty download. On the Switch .XCI, it’s a single, self-contained ~13.5 GB file – a masterstroke of compression and optimization. ACE COMBAT7 SKIES UNKNOWN DELUXE EDITION -XCI-....
Ace Combat 7: Skies Unknown Deluxe Edition (frequently found in It sounds like you're looking at a for