Usually, Texinfo changes the font to mark words in the text according
to the category the words belong to; an example is the
command. Most often, this is the best way to mark words. However,
sometimes you will want to emphasize text without indicating a
category. Texinfo has two commands to do this. Also, Texinfo has
several commands that specify the font in which text will be output.
These commands have no effect in Info and only one of them, the
@r command, has any regular use.