If you are a competent and accurate writer and are willing to spend the time reading the source code and writing good manpages please write a better man page than this one. Please contact the package maintainer and copy firstname.lastname@example.org in order to avoid several people working on the same manpage.
Even if you are not an accurate writer, your input may be helpful. Writing manual pages is quite easy, the format is described in man(7). The most important and time-consuming task is to collect the information to be put in the new manpage.
It is possible that the man page for the command you specified is installed and that your manual page index caches are out of sync. You should try running mandb(8).
Try the following options if you want more information:
foo --help, foo -h, foo -?
whatis foo, apropos foo
dpkg --listfiles foo, dpkg --search foo
find / -name '*foo*'
Additionally, check the directories /usr/share/doc/foo, /usr/lib/foo.
The documentation might be in a package starting with the same name as the package the software belongs to, but ending with -doc or -docs.
If you still didn't find the information you are looking for you might consider posting a call for help to email@example.com.