wpkg --verbose | -v ...
Short Hand
wpkg -v
The --verbose option is used to increase the verbosity of the wpkg tool. In most cases it helps getting more information about what wpkg is working on. It also changes the output of some commands such as the --directory-size command which then prints the size of each directory plus the total instead of just the total.
If --verbose doesn't give you quite enough messages to analyzie the work done by wpkg, you may want to look into using the --debug option as well. The --debug prints out a very large number of messages while working on your packages.
The opposite command line option is --quiet which removes the informational and the warning messages. When both options are specified, --verbose is used and --quiet is ignored.
Important Note
Contrary to many other tools, additional -v on the command line does not increase verbosity. For that purpose, try the --debug command line option instead.