`items` is documented in [the Common Wrapper Object][1]. It is an array of whichever object the given route returns.  

In the case of `/me/associated`,  `items` is an array of [`network_user` objects][2].

<br>
`badge_counts` is documented in [the `badge_count` object][3] and is just an object with 3 integer properties:

> **Fields**  
&nbsp;&emsp; bronze &emsp; integer  
&nbsp;&emsp; gold &nbsp; &nbsp; &emsp; integer  
&nbsp;&emsp; silver &ensp;&emsp; integer



  [1]: https://api.stackexchange.com/docs/wrapper
  [2]: https://api.stackexchange.com/docs/types/network-user
  [3]: https://api.stackexchange.com/docs/types/badge-count