The typical result of this function is to change the color of the taskbar icon, though it may be tweaked on specific platforms.
It is meant to unobtrusively tell the user that something relevant to them happened in the background and they should check the window when they get a chance. Upon receiving the keyboard focus, the window will automatically return to its natural state.
If the window already has the keyboard focus, this function may do nothing, because the user is presumed to already be giving the window attention.
requestAttention uses the _NET_WM_STATE_DEMANDS_ATTENTION atom on X11 and the FlashWindow function on Windows.
Requests attention from the user for this window.