[PLUG] Question on Ubuntu repositories

[Word Wizard]

I can't find a way to output a list of ALL Ubuntu repositories to
stdout.  The apt/get/sources.list does not show added third party
repositories like googleearth and the like. I can see them with the
Software Sources app or through Synaptic but there seems to be no way to
treat the entire repository list  as text, only as a graphical
screenshot file. Apt seems to have no "list" feature.  

I want a text file of the entire repository list to save so I can cut 'n
paste the desired third party additions to later installs 

 Is there another file for added third party repositories?

Maybe I'm missing something really basic here.  Any help?  

Thanx 

Word Wizard