Tota11y Plugin, from Khan Academy
All credit to Khan Academy and their awesome script. This extension just loads the script on all pages. See http://khan.github.io/tota11y/ for more details. v0.1.5 - 6/29/2016 - Updated script to 0.1.5 v0.1.3 - 2/2/2016 - Updated dashboard icon so it now toggles on/off, updated tota11y script to be 0.1.3, refactored scripting.