The C64 and the C128 have a memory for storing the color values of a character. The size of this memory is 1k x 4bit (2k x 4bit for the C128 which can do a double buffering), thus reading the value at a given address gives you the memory value in the 4 lower bits. The higher nibble can yield different results though.
10 PRINT PEEK(55296);:GOTO10
on a C64 emulator gave me something like
14 14 254 254 254 110 14 254 14
where 14 is the foreground color of the chars here and means light blue, the color that is set after a reset of the C64. 254 has the same lower nibble, but all bits set in the upper nibble.
My questions is, are
0000 the only possibilities for the high nibble or are other values possible as well?