combobox.tcl contains the following notice: this code is freely distributable without restriction, but is provided as-is with no warranty expressed or implied. Furthermore, in README.txt: This software is provided AS-IS with no waranty expressed or implied. This software may be used free of charge, though I would appreciate it if you give credit where credit is due and mention my name when you use it. I think that LICENSE="freedist" is a good enough approximation for this.
Fixed.