use 5.010;
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is equivalent to

BEGIN {
   $] >= 5.010
      or die "Perl v5.10.0 required--this is only $^V, stopped";
}

use feature qw( :5.10 );
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which is equivalent to

BEGIN {
   $] >= 5.010
      or die "Perl v5.10.0 required--this is only $^V, stopped";
}

use feature qw( array_base say state switch );
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Your program relies on the say and state features being activated, so if you remove use 5.010;, you need to add use feature qw( say state ); instead.

Note that those features were introduced in 5.10, so switching wouldn't gain you anything.