perl code question

[abcdef1]

Hi,

I have below code :

my($abc) = "fred<hello>3hello"; 
$abc =~ /^[^\d]{2,4}<([^>]+)>\d?\1$/; 

if (defined($1)) { 
print "$1\n"; 
} else { 
print "not found\n"; 

} 
} 

What is the code doing ?? what function of the regular expression

$abc =~ /^[^\d]{2,4}<([^>]+)>\d?\1$/; 

Please advice what it do ??