undefined

Guess what I saw while waiting for youtube to load?

A request to inboxsdk.com.

What is inboxsdk.com?

According to their website "The InboxSDK is a high-level Javascript library used to easily build browser extensions that interact with Gmail"

e.g. you can build a chrome extension that shows a modified version of Gmail to the end-user. Whether you realize it or not, the is a whole world out there just building Gmail Addons, there are multi-million-dollar startups that are just Gmail addons.

Definitely worth checking out https://www.inboxsdk.com/