+% why catcode 0 for \ in the above? To recognize \\ \{ \} as "escapes"
+% for the single characters \ { }. Thus, we end up with the "commands"
+% that would be written @\ @{ @} in a Texinfo document.
+%
+% We already have @{ and @}. For @\, we define it here, and only for
+% this purpose, to produce a typewriter backslash (so, the @\ that we
+% define for @math can't be used with @macro calls):
+%
+\def\\{\normalbackslash}%
+%
+% We would like to do this for \, too, since that is what makeinfo does.
+% But it is not possible, because Texinfo already has a command @, for a
+% cedilla accent. Documents must use @comma{} instead.
+%
+% \anythingelse will almost certainly be an error of some kind.
+