Tk is a free and open-source, cross-platform widget toolkit that provides a library of basic elements of GUI widgets for building a graphical user interface
Yhmmm... No.
SI = Special / Secret Intelligence TK is a codeword classification, standing for Talent Keyhole, meaning IMINT. TS/SI/TK is often used as a blanket “entry level clearance” for conferences, etc., as it is one of the most carefully controlled and restricted.
Kinda like Qt... :-)
I am glad you cleared that up for us.