Extended Tcl was designed and implemented by Karl Lehenbauer (karl at
procplace.com) and Mark Diekhans (markd at Kermodei.com), with help in the
earliest stages from Peter da Silva (peter at NeoSoft.com).
TclX 8.4 work was done by Jeff Hobbs.

As with Tcl, all of Extended Tcl is freely redistributable, including for
commercial use and resale (BSD-style license).