un-hide hidden form fields and make them editable
// ==UserScript==
// @name Display Hidden Form Fields
// @namespace http://diveintomark.org/projects/greasemonkey/
// @description un-hide hidden form fields and make them editable
// @include *
// @version 0.0.1.20190827001328
// ==/UserScript==
var snapHidden = document.evaluate("//input[@type='hidden']",
document, null, XPathResult.UNORDERED_NODE_SNAPSHOT_TYPE, null);
for (var i = snapHidden.snapshotLength - 1; i >= 0; i--) {
var elmHidden = snapHidden.snapshotItem(i);
elmHidden.style.MozOutline = '1px dashed #666';
elmHidden.type = 'text';
elmHidden.title = 'Hidden field "' +
(elmHidden.name || elmHidden.id) + '"';
}