All iPhones from iPhone 6 onward have a Reachability feature for accessing the furtherest edge of the display by double-tapping the Home button. Without a Home button, Apple’s devised a new way to use this helpful feature on iPhone X.
For a lot of people, the space that comes up when you invoke Reachability is considered wasted space. It becomes a giant gaping hole of nothingness on your screen any time you use the feature to one-handedly use your large-screened iPhone.
A new free jailbreak tweak called ReachBoard aims to make good use of that empty space by filling it with anything that may be residing in your clipboard.