DISC
From Just Solve the File Format Problem
Roxio TOAST can save a project file to a .DISC file for later use[1]. The project file only contains information about the disc layout and links to content, not the content itself. Compatibility might be an issue between earlier and later versions[2].
File Identification
Roxio Toast .DISC files have a data fork which has the magic header 5449534F and a Resource Fork, the latter containing metadata and paths to the content to be included on disc.
Screenshots
