That is not a subref. 
perl -E '  say ${\"FFF"}'
FFF

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All you are doing is referencing then de-referencing the returned value of the sub.

It is just a way to call a sub inside quotes - but I dislike the obfuscation it causes.

                All power corrupts, but we need electricity.

In reply to Re^3: -s file test operator only works in same directory by NetWallah
in thread -s file test operator only works in same directory by Bowlslaw

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