Description:
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The parameter of DOMNode::cloneNode is optional (see: http://php.net/manual/en/domnode.clonenode.php ), but it is described as required by reflection.

Test script:
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<?php
$rm = new ReflectionMethod(DOMNode::class, "cloneNode");
printf("%d\n%d\n", $rm->getNumberOfParameters(), $rm->getNumberOfRequiredParameters());
foreach ($rm->getParameters() as $param) {
    printf("Parameter #%d %s OPTIONAL\n", $param->getPosition(), $param->isOptional() ? "IS" : "IS NOT");
}

Expected result:
----------------
1
0
Parameter #0 IS OPTIONAL

Actual result:
--------------
1
1
Parameter #0 IS NOT OPTIONAL