There's a lot going on there, but this might be helpful, Chapter 8. Symbol Tables and Typeglobs (from Mastering Perl by bdf).

If you've ever seen the construct of locally mocking a subroutine, it's the same concept: 
# code not tested
sub test_this {
  my $stuff = call_to_external_service();
  return $stuff;
}

#...

# subroutine mock for a unit test, e.g.,
{
  no warnings qw/redefine/;
  my $expected = { some => 'expected result'};
  local *call_to_external_service = sub { return $expected, };
  # now call a test or something that calls
  is_deeply test_this(), $expected, qw{whatever...};
}

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The * on the LHS is like a wild card to match the "type" on the RHS. Another term related to this is monkey patching.

In reply to Re: Dollar Bracket Star ${*...} by perlfan
in thread Dollar Bracket Star ${*...} by snoopyjc

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