All files in this extension with the exception of the file js/wtf-8.js are
governed by the copyright and license set forth in LICENSE.txt.

The file js/wtf-8.js is
  Copyright Mathias Bynens <https://mathiasbynens.be/>
and is subject to the same license terms, though people wishing to
incorporate that code into other projects should consult
https://mths.be/wtf8 for the latest version.