Here I list some things, which would be very helpful for the further
development of cdrtools/cdda2wav, but I currently have no access to.
User support for the acquisition of these items is appreciated :-)

Access to all 'coloured books' from Philips/Sony
(Red/Yellow/Green/Orange/White/Blue,...).

CD-extra discs with a lot of features/entries in the data sectors (SUB_INFO*).

CD-text discs with a lot of features/entries. 
