Can you please tell me what is structure of anonymous hash (without name) is stored in Symbol Table how Perl decodes the value here

use constant {
STRAIGHT_LINE_ID => 1,
PRORATED_ID      => 2,
CBP_CUSTOM_ID    => 3};
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Here the anonymous has not any name

If the code is written like below then I can say the value can be fetched from memory with perticular name

use constant TICKET_FIELDS => qw(ticket_id
  date_modified
  date_created
);
my %ticket_fields = map {$_=>1}  TICKET_FIELDS;
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Please correct me whether I am wrong to store a anything in memory a variable is needed, and anonymous hash itself a memory and without name. How the value is fetched?