BTW, that .web file is not meant to be read directly (even Knuth doesn't read that file, except to make edits). The form in which it supposed to be read, and the form in which it was published as a book (though with some added typographical/indexing niceties) is the "woven" form, e.g. what you can find here: http://texdoc.net/texmf-dist/doc/generic/knuth/tex/tex.pdf