In case somebody missed it: Michael Steil has scanned and published the text of
Das neue Commodore-64-intern-Buch from 1990, which contains the commented source code of the Kernel and CBM Basic -- commented in German, that is. The announcement is at
http://www.pagetable.com/?p=718 , the code itself as HTML at
http://pagetable.com/c64rom/c64rom_de.html .
Note there is no statement about the legal situation. My knowledge of German copyright law is poor, though I do know that it can be amazing sane at times (relatively speaking). Data Becker ceased all operations this year (
http://en.wikipedia.org/wiki/Data_Becke ... operations). The book is not on sale any more.