It's a hash of hashes.(HoH)

You might be confused because hashes and arrays have two incarnations in Perl

• a reference which can be stored in a $scalar
• a "list form" ° which can be stored in variables with appropriate sigils like %hash or @array. (They are effectively containers for references but operating on lists)

Hashes consist of key => value pairs of scalars ( actually "string" => scalar pairs to be precise)

To realize nested hashes you need to put a hash reference into the value slot.

That's what's happening here.

See perldsc and perlref for more examples.

HTH :)

°) my wording