This page explains how Firefox decides whether to display a given IDN label (a domain name is made up of one or more labels, separated by dots) in its Unicode (i.e. normal) or Punycode (i.e. gobbledigook) form. Implementing this plan was covered by bug 722299. Background The Problem If we just display any possible IDN label, we open ourselves up to IDN homograph attacks, where one identical-lookin