Can access menu <Repo>/Settings/Webhooks

When I try to access the configuration panel for webhooks, I get the following error:

SyntaxError: JSON.parse: unexpected character at line 1 column 1 of the JSON data

It occurs in this code:
function updateUrl(config) {
var promise = _dollar2&#x27;default&#x27;.Deferred(function (defer) {
var contentPromise = window._AP.contentResolver.resolveByParameters({
addonKey: config.addonKey,
moduleKey: config.moduleKey,
productContext: config.productContext,
uiParams: config.uiParams,
width: config.width,
height: config.height,
classifier: 'json'
});

    contentPromise.done(function (data) {
        var values = JSON.parse(data);
        defer.resolve(values.src);
    });
});

return promise;

}

I joined the data variable content to this issue.