Every computer Keyboard has small Bumps on the 'F' and 'J' keys. It has to do with convenience, the keyboards on early typewriters were arranged alphabetically. The creators thought it'd make finding each letter pretty easy, but people found this layout to be inefficient.

One of the original designers, Christopher Latham Sholes, rearranged the keyboard to the QWERTY arrangement we know today. With a"." originally where the "R" would go and commonly occurring letter pairs - like "ST" - placed far apart.

The user's fingers rest on the ASDF and JKL; keys. This is called the "home row" and bumps are placed on the "F" and "J" keys to indicate to the user where the home row is and where to put your index fingers. Seasoned typists use the bumps to quickly navigate the keyboard. without looking down.