I think you get this interesting <1> syntax from the document:

'allow_srv_settings' => <1 | 0> (default 1)
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However that's not the Perl syntax, what it tells you is that, allow_srv_settings takes a boolean, either 1 or 0. If you don't supply a value, it defaults to 1.

So you could say:

'allow_srv_settings' => 1
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Or

'allow_srv_settings' => 0
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Or simply don't even mention it, which would be the same as saying:

'allow_srv_settings' => 1
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