The 1st instruction is a test to know if it's a ROM 1.0 or ROM 1.1 (it's the first byte that differs between the two ROMs).
#CC means ROM 1.1

You can consider that any test of a value in ROM (any address >= #C000) is to deetermine the type of ROM, as these values can't be changed by the user. Unless of course you are using the overlay RAM (which can't be done without an extension like disk drives).

EDIt: just realised you certainly needed an explanation for the whole code - sorry !