window move <number>

This moves the current window the specified number of positions down the screen. If the specified number would move the window off the screen, it is “wrapped” back to the top.

For example, assume there are 3 windows on the screen, and the current one is the topmost window. Moving it by 1 would place it in the middle, swapping position with the window that was in the middle.

This operation was already present in ircII2.1.5g.