What is OpenKeychain?

I would like to inform myself about OpenKeyvhain. I have no idea what it is and what is it for.
Why does it have a shop?
How important is it?
What is the purpose of it?

Maybe can someone point me to a article where all this is writen and explained. I did not find it here in the forum b




Ow sorry about that. I though it was a /e/ software and I only search the forum.
Ok great I will read the site.