perl -wE'
use Encode;
use Devel::Peek;
my $string = "ä";
Dump $string;
$string = decode_utf8($string);
Dump $string;'
SV = PV(0xbbca90) at 0xbe2878
  REFCNT = 1
  FLAGS = (PADMY,POK,IsCOW,pPOK)
  PV = 0xbe5530 "\303\244"\0
  CUR = 2
  LEN = 10
  COW_REFCNT = 1
SV = PV(0xbbca90) at 0xbe2878
  REFCNT = 1
  FLAGS = (PADMY,POK,pPOK,UTF8)
  PV = 0xbddf80 "\303\244"\0 [UTF8 "\x{e4}"]
  CUR = 2
  LEN = 10