Re: cannot understand Elisp manual node Glyphs

[Richard Stallman]

    I use it for my `visible-whitespace-mode' package.  It uses the
    display-table to cause whitespace to appear as graphic characters, and
    puts faces on them because they should appear distinct from normal
    buffer text.

I gather you remap these whitespace characters to other characters
as well as specifying a face.  Ok, we should keep that capability.