When you access the Magento Help Center, you first get to the Magento Knowledge Base.
What is Knowledge Base?
The Magento Support Knowledge Base is a collection of articles based on the support tickets that Magento customers or partners submit.
Every Knowledge Base article covers a real-life issue or question and may be viewed as a reply to a submitted support ticket helping others to solve a similar problem.
Does Knowledge Base replace DevDocs or User Guide?
The information in the Knowledge Base is designed as complementary to DevDocs, the User Guide, and other Magento publications, and only covers troubleshooting, answers FAQ's or highlights specific scenarios that have not been mentioned (for any reason) in the official documentation.