Does anyone know how Knuth originally defined the famous TeX macro
\TeX? Specifically, I want to know where I can find in, say, a TeXLive set of source files, of this macro being constructed.
I'm not asking so that I can recreate it or so I can better understand macros. I'm asking because I've been studying TeX source code/the TeXbook/tex.web for a while, but I'm still confused about its programming structure. All I can really gather is that some of it is written in WEB, Pascal, something called Pascal-H, then TeXLive made WEB2C to translate it to C, etc., so I feel that a concrete identification of where
\TeX is defined in TeX source code would be helpful in sorting this stuff out.