Document jow \verb suppresses ligatures

base/doc/usrguide.tex

@@ -838,7 +838,9 @@ \subsection{Typesetting verbatim-like material}
 users often associate with \enquote{verbatim} are not automatically activated,
 e.g., a monospaced font. Material grabbed by the \texttt{v}-type argument does
 not automatically suppress ligatures: with modern \TeX{} engines, this largely
-can be done without the token manipulation which \cs{verb} uses.
+can be done without the token manipulation which \cs{verb} uses. (In \cs{verb},
+ligatures are suppressed by making characters active and inserting a zero-width
+kern before the character itself.)
 
 The \cs{verb} command also selects a monotype font: this is not intrinsic
 to verbatim material, so will need to be set up using for example \cs{ttfamily}.