use vars qw(%unk, @foo);
my(@ulist) =  
	map{      # Sort descending
	    $_->[1] 
	    } sort{ 
		$b->[0] <=> $a->[0] 
		} map{ 
		  [scalar(@foo=split(/\t/, $unk{$_})), $_ ] 
		    } keys %unk;

##</code><code>##

	  [scalar(split(/\t/, $unk{$_})), $_ ] 

##</code><code>##

Use of implicit split to @_ is deprecated at extractions line 393.