Erica asks CLs to have an eye on that FAQ. Here is my feedback, I hope it will help!
Who are you targeting with that extension? I don't understand if it is people who already use Wikimedia projects. If not, there is sometimes some information missing about the culture and tools we use (what are editathons, notifications or OAuth, for example?)
Is it relevant for people who don't know the project to know it is Ruby on Rails tool as first information. :)
On the third section, you should add links to all roles, because people may want to know more about.
Do you plan to add a section about how to activate that extension?
I've also added some links, HTH