This is not especially good in any sense, but is kinda unique still.
Because imho its a first CM implementation with only direct access
to all (masked) context statistics and with CM-like compression ratio.
That is, there're no hashes or trees - only static tables where
each element corresponds to a specific context.
Context masks are pretty funny - check the .idx files in archive.

[ mix_test 09h2x4a CM coder (87M stats memory) ]
book1.rc: 222010
enwik6.rc: 252742
wcc386.rc: 269768

[ mix_test 09h2x4b CM coder (310M stats memory) ]
book1.rc: 218899
enwik6.rc: 248272
wcc386.rc: 267258