This is no ordinary geocaching trading item!
The Annex is a Travel Bug Dog Tag Travel Bug, traveling from geocache to geocache on a very specific mission.
If you do not intend to log your visit on the Geocaching.com web site, please DO NOT TAKE THIS ITEM. Its travels and its progress requires you to log that it is being taken from this geocache. You will also need to log when you place it in another geocache. It's easy!
If you are willing to log your part of this Trackable's journey and place it in another geocache as soon as possible (after you log your find), grab it from this geocache.
My Current Goal:
The Annex
There are no clues on the Annex page that would help you find any of the letters that you need to discover the key for the Little Free Library.
noun
1. a building joined to or associated with a main building, providing additional space or accommodations.
verb
1. to attach, append, or add, especially to something larger or more important.

This annex is one used for trackables and according to the definition this is associated with the main building (the little free library) to provide additional space or accommodations.
Inside the annex you will find many trackables to discover or trade. You do however need a key to get into the annex which can be found inside the little free library where other trackables can be discovered or traded.
If the red flag is up that is an indication that there are trackables inside the annex.