Version: 5.3 (switch to 5.4b)
Как предложить изменения (contribute) в Unity
Step 2: Fork the repository you want to contribute to

Step 1: Get a Bitbucket account

Our open-source components are hosted on Bitbucket under the Unity-Technologies team. You don’t need to be logged in to access the repositories and clone the source code, but you will need an account in order to be able to contribute your changes.

Чтобы начать, посетите страницу создания аккаунта на Bitbucket.

If you don’t want to make a new account, Bitbucket supports OpenID, which will let you log in with your Google, Facebook, Twitter, or GitHub account.

Как предложить изменения (contribute) в Unity
Step 2: Fork the repository you want to contribute to