Armed with a text editor

[Epiphany Extension]
Name=Expand Four Tabs
Description=Expands tabs when there are four or more; this avoids scrolling.
Authors=Michael Urman <murman+ephy@gmail.com>, Stefan Stuhr
Version=1
URL=http://www.tortall.net/mu/wiki/EpiphanyExtensions

[Loader]
Type=python
Module=expand-four-tabs