It is common to package an extra disc of material with some Releases. These are labeled with the DiscNumberStyle.
A bonus disc is a disc of material that is considered extra to the Release. It is used to show the difference between true multi-disc releases (eg, The Beatles - The Beatles (disc 1) & (disc 2)), and normal releases augmented by bonus tracks (eg, The Fall - Hex Enduction Hour & Hex Enduction Hour (bonus disc)).
Note that the presence of bonus tracks on the primary disc of a release does not mean any subsequent discs aren't bonus discs. A distinction is always made between true multi-disc releases and bonus discs.
Also note that the ReleaseAttribute of bonus discs are not necessarily the same as the release they were distributed with. Use the attribute correct for the bonus disc on its own.
- "Mother Nature Calls (bonus disc)"
- "Greatest Hits (bonus disc: Acoustic Hits)"