[o11c]

It's only "compressed" if it was made by compress(1) in France. Otherwise it's just sparkling entropy coding.

For reference:

    1490 xmas-with-leading-comment.c
     913 xmas-without-leading-comment.c
    2357 xmas.out
    1297 xmas.out.9.Z
    1038 xmas.out.10.Z # actually better than with more bits!
    1048 xmas.out.11.Z # compression with 11..16 bits have the same size
     319 xmas.out.1.gz # compression levels 1..2 has same size
     317 xmas.out.3.gz
     307 xmas.out.4.gz # compression levels 4..9 have same size

Note that despite looking hard I haven't found a version of `compress` that supports `-H`, which is referenced and decompressable by gzip. I'm not sure how common it was in the wild.