@item setting-constant
@code{"Attempt to set a constant symbol"}@*
-The values of the symbols @code{nil} and @code{t}
-may not be changed.@*
@xref{Constant Variables, , Variables that Never Change}.
@c XEmacs feature
@item undefined-keystroke-sequence
@code{"Undefined keystroke sequence"}@*
-@c XEmacs feature
-@item underflow-error
-@code{"Arithmetic underflow error"}@*
-
@ignore FSF Emacs only
@item undefined-color
@code{"Undefined color"}@*