What is meant by “mods”? In this case, “mods” refer to modifiers, that is to say ⇧ Shift, ⎈ Control, ⎇ Alt, and ◆ GUI. The bars or the dish found on F and J help to find back the home position without looking at the keyboard - this is especially important for relatively big keyboards which require you to move your hands to hit some of the keys like for example Backspace or the arrow keys on a classic TKL and thus throw you off home position. This row is called the “ home row” because if one were to follow touch typing technique, this is the row of keys on which your fingers are supposed to rest on.
On an English QWERTY keyboard this would be The “home row” refers to the middle row of alpha keys.
