[NeoKlafilin]

Я так понимаю формируется он тут:

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Sys.Application.add_init(function() {
    $create(AjaxControlToolkit.NoBotBehavior, {"ChallengeScript":"var e = document.getElementById(\u0027ctl00_cp_NoBotID_pcnb\u0027); e.offsetWidth + e.offsetHeight;","ClientStateFieldID":"ctl00_cp_NoBotID_NoBotID_NoBotExtender_ClientState","id":"ctl00_cp_NoBotID_NoBotID_NoBotExtender"}, null, null, $get("ctl00_cp_NoBotID_NoBotID_NoBotLabel"));
});
Sys.Application.initialize();
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</script>