Profile repo is a new functionality that GitHub has released recently.
The repo is https://github.com/userName/userName.
That makes the GitHub profile page like the following.
In my case, I added a gif that generated by my Instagram post.
Step 1: Add a new repo
Step 2: Use your GitHub name as repo name
Step 3: Edit README.md
Step 4: Go to https://github.com/userName
Here is a list of people who are using Profile repo
This might be helpful to make your repo great.