Texinfo has an @if... environment for each output format, to
allow conditional inclusion of text for a particular output format.
@ifinfo begins segments of text that should be ignored by TeX
when it typesets the printed manual. The segment of text appears only
in the Info file and (for historical compatibility) the plain text
output. The @ifinfo command should appear on a line by itself;
end the Info-only text with a line containing @end ifinfo by
itself.
The @iftex and @end iftex commands are analogous to the
@ifinfo and @end ifinfo commands; they specify text that
will appear in the printed manual but not in the Info file. Likewise
for @ifhtml and @end ifhtml, which specify text to
appear only in HTML output. And for @ifplaintext and
@end ifplaintext, which specify text to appear only in plain
text output. And for @ifxml and
@end ifxml, for the XML output.
For example,
@iftex
This text will appear only in the printed manual.
@end iftex
@ifinfo
However, this text will appear only in Info (or plain text).
@end ifinfo
@ifhtml
And this text will only appear in HTML.
@end ifhtml
@ifplaintext
Whereas this text will only appear in plain text.
@end ifplaintext
@ifxml
And this will only appear in XML output.
@end ifxml
The preceding example produces the following line: And this text will only appear in HTML.
Notice that you only see one of the input lines, depending on which version of the manual you are reading.