GitHub is not Git.
Git is by far the most widely used VCS. The majority of code hosting services use it.
Yes, I am aware. I didn't claim anything else.
My clients don't use GitHub.
Most of my clients do use Git. (some use other VCS)
What made you think I thought differently?
Because the comment you replied to never mentioned GitHub. I thought you didn’t know the difference. Linus created Git.
I am contributing to a few open source projects on GitHub here and there though.