The style guidelines address this case and refer to a similar example:
Some releases separate bonus tracks from the listed tracks by one or more tracks that contain only silence. A version of Nine Inch Nails’ Broken uses the full 99 tracks available to the CD format; tracks 1 to 6 are music, tracks 7 to 97 are silence tracks, and tracks 98 and 99 are ‘hidden’ tracks. As indicated, these should be named [silence].