This keyword can be used to produce reports about what is left in the image when delivery is over. It is useful when determining which remaining parts of the system are not needed. When nil, no reports are generated.
Possible values of :call-count are:
After running the application, the image is scanned, and the size of each object, in bytes, is printed out. This produces a lot of output, comparable in size to the delivered image itself, so make sure you have plenty of disk space first.
After running the application, the image is scanned, and the name of each symbol found is printed out. A + sign is printed next to the symbol if it is non-nil. If the symbol is fboundp, the call count (that is, the number of times it was called while the application ran) is printed too.
Delivery sets the call counter for all symbols to 0 before the saving the delivered image.
Interpreted functions do not maintain a call counter.
This has the same effect as :all, but only symbols with function definitions that were
not
called are printed.
The output is written to a file or the standard output. You can specify its name with :diagnostics-file.
LispWorks Delivery User Guide - 10 Aug 2017