1. What is that ?
this is a small C library with a collection of small useful stuff such as:
 * Index allocator
 * Linked list implementation, looks like a linux kernel one
 * Collection of the binary search tree implementation:
   * Btree
   * AVL
   * Red black
   * Splay

2. Is it useful ?
I hope yes, usually I have a lot of tools or applications to implement required 
to use index allocation, or some kind of structures to search within.
I guess it might be useful for everybody who looks the same thing (implement 
the same boring stuff each time isn't productive).

3. Is it stable ?
Yes, very stable. But if you will find a bug, please report me.
Actually it used in a lot of my projects (now most of them is a closed source), 
but I decide to make it open, anyway I should to do it, because initially 
it was LGPL'ed, and has a roots from my old open source project.

4. How to build ?

4.1. Just type ./autogen.sh, and you will have a configure script with a 
common autotools options.

4.2. To build the Debian package: debuild -i -us -uc -b

5. Are there new features coming ?
I hope so, will add a new features as soon as possible. But generally I don't
have any plans about it.