"Background info" refers to the information or details that provide context or a deeper understanding of a particular topic or situation. It gives a foundation or backstory to help explain the main subject. Full definition
Besides the main story, there are several optional character side stories that give more background info on the different characters such as their problems, fears or needs. (handheldplayers.com)
Such important background info for us to know if we want to really get to the root of someone's problem. (ifnacademy.com)
Could you give us some more background info about your own situation which gave you «instant approval». (milevalue.com)