GNU Emacs Lisp Reference Manual
23.3.5 Window Header Lines
Starting in Emacs 21, a window can have a header line at the
top, just as it can have a mode line at the bottom. The header line
feature works just like the mode line feature, except that it's
controlled by different variables.
- Variable: header-line-format
- This variable, local in every buffer, specifies how to display the
header line, for windows displaying the buffer. The format of the value
is the same as for
mode-line-format (see section 23.3.1 The Data Structure of the Mode Line).
- Variable: default-header-line-format
- This variable holds the default
header-line-format for buffers
that do not override it. This is the same as (default-value
'header-line-format).
It is normally nil, so that ordinary buffers have no header line.
