title: What is the "admin" database in mongodb?
body: <p>I was practicing ont mongodb documentation : <a href="https://docs.mongodb.com/manual/tutorial/enable-authentication/" rel="noreferrer">https://docs.mongodb.com/manual/tutorial/enable-authentication/</a></p>
  
  <p>and I can't figure out if the "admin" database in the example is just a database created for the tutorial or if it is a built-in database made specifically for managing admin users.</p>
  
  <p>Thanks in advance.</p>