In Emacs, start- and end-of-header lines can be used to enclose commands that
globally affect the document in the Texinfo preambule. This allows you to
format only part of a Texinfo file for Info or printing.
See The texinfo-format… Commands.
A start-of-header line is a Texinfo comment that looks like this:
@c %**start of header
Write the start-of-header line on the second line of a Texinfo file.
Follow the start-of-header commands that globally affect the document
formatting, such as @settitle, @synindex or
@footnotestyle; and then by an end-of-header line.
A end-of-header line is a Texinfo comment that looks like this:
@c %**end of header
The odd string of characters, ‘%**’, is to ensure that no other
comment is accidentally taken for a start-of-header line. You can
change it if you wish by setting the tex-start-of-header and/or
tex-end-of-header Emacs variables. See Formatting and Printing in Texinfo Mode.
The start- and end-of-header lines are not part of the Texinfo format specification, which is why they are implemented with comments.