It is important to address the elephant in the room immediately: most official export keys have expired. Due to the way music licensing works in the gaming industry, Harmonix was only granted the rights to offer these "export" licenses for a limited number of years. Once those contracts lapsed, the export keys were removed from the PlayStation Store and Xbox Live Marketplace.
Here are the most likely interpretations and the corresponding feature descriptions: rock band song export key
The is a one-time purchase or digital entitlement that grants a player the legal right to "export" the soundtrack of an older Rock Band disc into the library of a newer game. This system was designed by Harmonix to reward long-term fans by ensuring their song libraries remained accessible across console generations, primarily moving from the PlayStation 3/Xbox 360 era to the PlayStation 4/Xbox One. 2. The Export Process by Title Rock Band Song Export Key — What it
Each game had a slightly different method for transferring its library: Here are the most likely interpretations and the
: These have long since expired. If you did not purchase the export key while it was active (circa 2010–2015), you can no longer export these full soundtracks. Rock Band 3 Export
