What are git github, gitlib and gitlab, and what are the differences?

Question

I saw someone talking about gitlib/gitlab, so the question is, what are git github, gitlib and gitlab, and what are the differences?
I only know github;

Answer 1

git is a version control system, a command, and a tool
gitlib is a development library used to implement git functions
github is an online code warehouse based on git, including a website interface, open to the Internet
gitlab It is an online code warehouse software based on git. You can use gitlab to build a system similar to github. It is generally used to build git private servers in internal networks of companies, schools, etc.

Answer 2

gitlib is a git library, a library

gitlab is the laboratory of git, a website

github is the hub of git, a website

git is a version control system.