What are the letters and numbers above the ISSN called, and what do they mean?

What do the letters and numbers above the ISSN mean, and what are they called?

HAC P ALZAA

TRA-HAC-ALZAA-AUS-1

I'm presuming the "AUS" part is because it's the Australian version of the game.

Solution 1:

Every Nintendo game I checked has that "TRA-HAC" part, that should identify the Nintendo company.

This is true for every copy I own except for Super Bomberman R, made by Konami, and its code is "TSA-HAC". So my guess is that the first part identifies the software house.

HAC itself is a mystery and

it's speculated to stand for Handheld And Console.

AUS definitely stands for Australia, since my Italian copies have ITA.

"ALZAA" instead is an alphanumeric unique code that identifies the game (it should belong to Pokemon Sword). Those codes start from "AAAAA" which, I can confirm, is actually The Legend of Zelda: Breath of the Wild, since it's the very first game lauched for the Nintendo Switch.
So I guess every other game just follows it... alphabetically.