>
>doesn't say what the unit of the size field is.
>

I agree it's not super clear but it does mention that it's in kilobytes:

       A  log  can  be  archived because of two reasons.  The log
       file can have grown bigger than a  preset  size  in  kilo-
       bytes,  or a preset number of hours may have elapsed since
       the last log archive.

I'd say send-pr it.

James