(F) A string of a form C<CORE::word> was given to prototype(), but there
is no builtin with the name C<word>.
+=item Can't find %s character property "%s"
+
+(F) You used C<\p{}> or C<\P{}> but the character property by that name
+could not be find. Maybe you mispelled the name of the property
+(remember that the names of character properties consist only of
+alphanumeric characters), or maybe you forgot the C<Is> or C<In> prefix?
+
=item Can't find label %s
(F) You said to goto a label that isn't mentioned anywhere that it's
=item Misplaced _ in number
-(W syntax) An underline in a decimal constant wasn't on a 3-digit boundary.
+(W syntax) An underscore (underbar) in a numeric constant either
+immediately followed an earlier underscore; or an underscore ended a
+numeric constant, or, in the case of decimal constants, an underscore
+began or ended its fractional part. (If you try to begin a numerical
+constant with an underscore, it won't even be recognized as a number.)
=item Missing %sbrace%s on \N{}