CD-Text is an extension of the Red Book Compact Disc specifications standard for audio CDs.
The specification for CD-Text was included in the Multi-Media Commands Set 3 R01 (MMC-3) standard, released in September 1996 and backed by Sony.
This information is usually stored in the subchannels in the lead-in area of the disc, where there is roughly 5 kilobytes of space available.
Its special null handling is not necessary for computer DBCS code pages, as they are "hybrid" with ASCII and compatible in the NUL behavior.
(MMC-3 is written confusingly here – it describes the encoding as "ASCII" in the pack type table despite mentioning the BNCPI flag modifying its behavior later.)