WordShell is a bash script, that calls upon several other helper programs (e.g. lftp) to perform its work. If you can hack bash, you can hack WordShell. WordShell also employs a PHP helper program, wp-wordshell-manager.php which by default is downloaded into ~/.wordshell/wp-wordshell-manager.php. If you can hack PHP, then you can also tweak that program to your heart’s content.
Please do send us any patches you make, and we can share them with others. If your patch is particularly notable, then we will give you a free subscription to future WordShell upgrades. You will need to give us a copyright grant without reservation to include your patch within future versions of WordShell.