[kronolith] Two config questions

[cjdl01]

> This depends on your preferences.  Please use hooks provided in  
> kronolith/config and configure $_prefs['search_sources']['hook'] =  
> true;
>

Thanks Anant, but I would like to ask for a little more clarification.  
  I have looked into my ~/kronolith/config/prefs.php, and found this  
code:

// Address book(s) to use when expanding addresses
// Refer to turba/config/sources.php for possible source values
//
// You can provide default values this way:
//   'value' => json_encode(array('source_one', 'source_two'))
$_prefs['search_sources'] = array(
     'value' => ''
);

But I'm confused, there is nothing in my turba/config directory called  
sources.php.  I want Kronolith to look through all the address books  
that the user in question has access to (which is what I would think  
most people would want), so what constitutes a source?  Certainly not  
the name of the address book.. is there a source that is equal to "all  
the address books I have access to"?

I'm not sure I understand what is being implied with this line:
//   'value' => json_encode(array('source_one', 'source_two'))

Not sure what json_encode is... is that an example, or do we take it  
literally?

Thanks again.