The homepage of the documentation subproject is here:

It contains news about our activities, links to the docs we've already published, plans for the future, etc.

If you're serious about writing docs for Firebird, the first thing you should do is subscribe to the mailing list where we discuss our plans and our work. This list is open to everybody, and subscribing commits you to nothing. Send an email to:

with the word “subscribe” either as subject or as the first and only line in the message body. Alternatively, you can fill in the form on this webpage:

Whichever method you choose, you'll receive an email message from the list robot within minutes. Follow the instructions in that message and you're on the list.