On ActiveCollab website's frontpage, there is a mention :

Extend and Integrate.
If you have special needs you will love activeCollab. Use plugins to extend the system and make it work exactly how you want it to. Feel free to integrate activeCollab with other tools and services through an API.

I tried searching the forums for "API" but the system tells me I cannot search for less than 4 character (*sigh*)... :)

So now I'm here : is there any documentation for this API ?
Thank you!