[Until quite recently, Expect was most often a "big tclsh".]
A big tclsh or big wish is a term often used when referring to the practice of statically linking into a single executable additional extensions.
Don Porter (and Jeffrey Percival) nicely illustrate re-engineering of an existing "big wish" application to use a loadable package [L1 ].
DGP Note that reference only starts the journey that can be taken.