On coxeter we have changed the default in firefox so that URLs that have non-ASCII characters will be displayed using punycode (which only uses ASCII) to alert users to potential homograph attacks. If you need to allow non-ASCII characters in URLs then you can type about:config in the Location Bar (sometimes called the Address Bar) to change your setting for the network.IDN_show_punycode variable to false.
Non-ASCII characters in URLs in firefox
April 24, 2017 by
