list-matching-lines-prefix-face

list-matching-lines-prefix-face is a variable defined in `replace.el'.
Its value is

shadow

Documentation:
Face used by M-x list-matching-lines to show the prefix column.
If the face doesn't differ from the default face,
don't highlight the prefix with line numbers specially.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 24.4 of Emacs.