About libinput and evdev

[starcold14]

Hi，Xorg，
I am a newbie of xorg. I am very confused about libinput, x86-input-libinput, 
xf86-input-synaptics, evdev:
1.x86-input-libinput uses libinput, does xf86-input-synaptics use libinput too?
2.what is the relationship of x86-input-libinput and xf86-input-synaptics, are 
they two have conflicts ?
3.dose libinput or xf86-input-synaptics or xorg use evdev directly?
4.is there any graph or document discribe these things's relationship？
QAQ（anyone helps！）
Thank you.