While testing this new feature, I noticed the Clipboard function doesn't escape the first { and none of the quotes in the Evaluator expression.
It creates this button:
Rename PATTERN=* TO="{=d = RegEx(name, ".*?((19|20)\d{2}).*", "\1", "e"); d == "" ? Cancel() : d=}\*" IGNOREEXT AUTONUMBER
But the code needs to look like this to work:
Rename PATTERN=* TO="{{=d = RegEx(name, "".*?((19|20)\d{2}).*"", ""\1"", ""e""); d == """" ? Cancel() : d=}\*" IGNOREEXT AUTONUMBER