I've been rummaging through Unity's source code (Shell Interface) and I was a little curious about something; where in the code are you supposed to find positional code? I'll clarify a bit with some examples. How do you find in the code what tells the Launcher to sit on the left side of the screen? Where in the code does it tell the "Session" button on the panel (top) to sit at the very right of the screen?

I guess my real question is how do I find this out for myself? I've looked through a big portion of the source code and can't find anything related to the actual position of these items, only their sub-items like text-align. Any guidance on this would be much appreciated.