GSPlaceholderString -characterAtIndex:

[Enrico Sersale]

In -base 1.10.0 this method raises an exception instead of, simply, returning 0.
This breaks all the code that uses things like this:

  NSString *s = [NSString string];
  s = [s stringByAppendingString: @"asd"];

(or stringByAppendingPathComponent or stringByAppendingFormat, etc.)

Actually it seems that there are two places affected by this: gsdoc.m and 
NSPrinter.m.