Laravel 4 loading class and facades

I want to know how Laravel loads a class via Facades.

I came across this answer which said the DB

alias / facade class loaded the code

here /vendor/laravel/framework/src/Illuminate/Database/Connection.php

I tried following the guidelines in the answer and following what the code from index.php does, but couldn't figure out how DB

Facade loaded the class Connection

.

I am a little more confused because the answer said the class is Connection

loaded, but this class has no method Connection

. However, the documentation says and I was able to use a connection method like

DB::connection('my-connection-name');

here's the docs link for that

I want to know where this is all mapped and how the download is happening. I'm assuming composer has automated the mapping, but where does this happen when my app loads?