http://www.perlmonks.org?node_id=886211


in reply to Re^3: how ! operator works
in thread how ! operator works

That refcount (2147483647) looks strangely familiar.
Just print it out in hex and you'll see:
7FFFFFFF
which is a clear indication that this is the largest positive integer you can stuff into a signed 32 bit integer (2's complement).

So yeah, your guess is very likely correct.