Just playing around with some of the Google Plus badges. I really like this one a lot. It's amazing all the fun stuff that keeps popping up like this g+ License.
On this one, as you can see on the image below, they pull your introduction section off your Google Plus profile. At the bottom you see "license no:" That's simply the i.d. number assigned to your profile in the url address of your profile.
- i.e.: My profile url is: https://plus.google.com/u/0/109631753156353457791
You can click the link. It'll take you to my Google Plus profile.
The g+ License is simply an image created with your info on it. If I want a different image/avatar, I will need to change that in my profile edit options, along with any of the other data. The License page that you use to create it offers you to right click and save image to your hard drive. Once you do that you can upload the image and use it all over the web.