It would be nice to have a little plain English description for each example as well. E.g. the suppress example[0] kind of does this with a comment, but the Enum example[1] isn't really clear about what advantage it creates over Python 2.
At the bottom there is a link to the inspiration for this project. It has a much better format. "You can already do this:" "Now you can do this:" which actually shows the differences. Really a simple explanation of what's happening and why it's useful and why it's better than py2 would be nice. Especially for newer programmers who are trying to figure out which version to start with.
I've added some more comments as many people asked for them. I initially tried to keep it very simple to the point where you read a little piece of code and think to yourself that's really cool and I want to try it out in Python 3. But you're right and a little text can help put things in the right context which might not be immediately obvious.