This is the slice detail editor.

Use the up and down arrow keys to navigate the menu.

Use the left and right arrow keys to change values, or you can type in numbers.

If you press ENTER or SPACE in the "Slice Type" you can choose a new type from a list. Different slice types have different options.

X and Y are the position of the slice relative to its parent. You can press ENTER or SPACE on these to reposition the slice using the arrow keys.

Width and Height are the size of the slice. You can press ENTER or SPACE to resize the slice using the arrow keys.