its the stock CoD PC layout that the XIM4 suggest as default i think, this doesnt mean its the most common or a good button layout in general

the best layout is the one that you customize to your habbits, how you hold the mouse, and especially what devices you use

eg i cannot stand to have ADS on right mouse click, it reduces your mouse precision because of the unnatural pressure you put on the mouse with one finger while having to sensitive click the other button
eg thumb button for ADS or keyboard key is a much better option imo
but thats just how i like it, as i said everyone is different and therefore its definitely a good investment into testing different layouts until you found your own
