xpconnect-sample.html questions

[Jimmy Chen]

In xpcom/sample/xpconnect-sample.html, there are two lines
that I don't understand, can someone tell me what they are:

1. netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect");
- what's it doing ?
- what's this "netscape" object ?
- where is it created ?

2. var sample =
Components.classes["@mozilla.org/sample;1"].createInstance();
- What's this "Components" object ?
- where is it created ?

many thanks,
Jimmy