This program lets you type UTF-8 everywhere (like in web browser
forms for example).

UTF-8 installs an input-handler into input.device that translates all
characters above ASCII-128 (i.e. ISO-8859-1
and possibly others) typed on the keyboard (or otherwise sent through
input.device) to UTF-8 codes.
This makes it possible to edit XML documents or other documents
using UTF-8 character encoding. It also enables you to fill in
web forms on Internet sites that only accept UTF-8.

It may not be of that much use to native English people, or people
requiring a full unicode set, like Asians, but most Europeans can
benefit greatly from this.