a triangle by default, not a solid box.
Emacs supports many other characters sets aside from ISO 8859, but it
cannot display them on MS-DOS. So if one of these multibyte characters
-appears in a buffer, Emacs on MS-DOS displays a solid box instead of the
-character.
+appears in a buffer, Emacs on MS-DOS displays them as specified by the
+@code{dos-unsupported-character-glyph} variable; by default, this glyph
+is an empty triangle. Use the @kbd{C-u C-x =} command to display the
+actual code and character set of such characters. @xref{Position Info}.
@findex codepage-setup
By default, Emacs defines a coding system to support the current