"International" could mean any of the other 3 variants besides ATT depending on the seller.
eBay sellers are notoriously bad at accurate listings. They simply find an entry and copy/paste when it comes to Windows Phone. Few of them seem to actually know what they have in hand.
For instance:
New in Box Nokia Lumia 1520 16/32GB Unlocked Smartphone Windows Phone ALL COLORS | eBay
Says 16/32GB International. Bull snot, only the ATT had 16GB. They have a dropdown to select and only 16GB is active, 32 being greyed out. The spec is copied from GSMarena and lists radio spec for all 4 variants. They have no idea what they are selling or how to communicate what it is clearly. You might end up paying $200 for a Lumia 520 with these clowns.
This one:
Nokia Lumia 1520 RM-940 - 32GB - Black (AT&T Unlocked) Smartphone New 6438158640337 | eBay
Says it is the RM-940 in the rare 32GB (32 is rare for ATT), but the picture shows a device without pogo pins. All AT&T 1520s (and ONLY ATT 1520) has three pogo pins on the back for the PMA charging cover. They also neglect to state what LTE Bands are on board. Battery capacity says 2370 mAh, yet each and every 1520 comes with 3400 mAh battery. More foolishness.
BINGO!!! Check the box. That one is legit if the pics match what is being offered.
Nokia Lumia 1520.3 RM-938 RARE Smartphone 32GB 20MP Unlocked Bundled Free Ship!! | eBay