The foreground contains the applications the user is working on, and the background contains the applications that are behind the scenes, such as certain operating system functions, printing a ...
If you open the Command Prompt, it should be evident that the background color is black. However, there are those who would prefer to change the color but have no idea this is a possibility.
Regarding this problem, new delivery optimization settings were introduced to save network consumption by allowing users to set the bandwidth limits for background and foreground downloads manually.