$ perl -MScalar::Util=blessed,reftype -E'
   open my $fh, ">", \my $buf;
   say reftype($fh) // "[not a ref]";
   say blessed($fh) // "[not blessed]";
   say reftype(*$fh{IO}) // "[not a ref]";
   say blessed(*$fh{IO}) // "[not blessed]";
'
GLOB
[not blessed]
IO
IO::File