This is the help text of compileall:

 usage: python compileall.py [-l] [-f] [-q] [-d destdir] [-x regexp] [-i list] [directory|file ...]
 -l: don't recurse down
 -f: force rebuild even if timestamps are up-to-date
 -q: quiet operation
 -d destdir: purported directory name for error messages
    if no directory arguments, -l sys.path is assumed
 -x regexp: skip files matching the regular expression regexp
    the regexp is searched for in the full path of the file
 -i list: expand list with its content (file and directory names)
 -b: Produce legacy byte-compile file paths

1) I do not understand the help of -d and -i.  Experimenting with the script, reading the code and eventually looking at the file history would certainly clear that.

2) The short usage line at the top also lacks mention of “-b”.

3) (minor) I want to rephrase -x, -d and -b.

Bug week-end candidate!