Each title is given a 64-bit title ID that uniquely identifies the title; if two titles have the same ID, then they are most likely different versions of the same title.
The upper 32 bits of each ID describe general properties of the title, while the low 32 bits are the title itself, and usually uniquely identify the title.
Types of titles
The following types of titles have been seen.
|00050002||eShop title demo / Kiosk Interactive Demo|
|0005000C||eShop title DLC|
|00050010||System Application, last byte OS version|
|0005001B||System Data Archive, last byte OS version|
|00050030||Applet title, last byte OS version|
The upper 16 bits seem to be the the platform ID, which is 5 for the Wii U. The lower 16 bits appear to be a bitmask; the following bits are recognized:
|0x4||Patches another title|
|0x20||Runs in background|