laravel - What does OAuth2 do?

Question

There is a Laravel Passport in the just released laravel 5.3, which is explained like this:

Laravel Passport encapsulates all elements for deploying an OAuth2 server. This package is optional and provides complete scope settings, Vue.js components for generating and revoking tokens, and many more to mention.

Don’t quite understand what OAuth2 does? When will it be used?
I searched on Baidu, but I don’t understand it very well. I would like to ask you to help explain it.

Answer 1

Let’s talk about a common application.
QQ login, WeChat login and other third-party logins all use oauth authorization

Answer 2

Open authentication and authorization network standard

Answer 3

Similar to how you can use your Weibo account to associate your email, it’s just a standard to unify user authorization

Answer 4

Teacher Ruan’s is very detailed and understandable