I would like to understand what goes on after I boot my PC. What I see is a login request mask where I enter userid and password. Next I see my personalized (xfce) desktop - if everything works!
The login request comes from the gtk-greeter (e.g.), however, the x window subsystem is involved in displaying it as a graphical object. My understanding or assumption: ultimately my login parameters become input of a login command, which is generated under the cover, so to say. I would like to understand, which other units / services are involved in the login process.