BIRT Report Designer (and other associated BIRT tools) can be downloaded from here on the eclipse foundation site.

Information on which kind of download to choose (All-In-One or RCP), and installation instructions can be found here on the main BIRT project site.

Older versions of BIRT can be downloaded from here on the eclipse foundation site.

Some commonly used past versions are:
BIRT v4.8
BIRT v4.6
BIRT v4.4.2

BIRT Runtime can be downloaded from here on the eclipse foundation site.

To download the runtime, select the required version of BIRT and then download the birt-runtime-*.zip

The BIRT project website is hosted at https://eclipse.github.io/birt-website

The BIRT project is maintained by a wide variety of people and companies.

“BIRT is supported by an active community of committers, contributors, and users […] at Eclipse.org. The Open Standard Business Platform Project (OSBP) and its Open Standard Business Application Working Group (OSbea) also support BIRT.

The project is driven by a team of committers, contributors, and companies. BIRT was originally initiated and sponsored by Actuate with contributions from IBM and Innovent Solutions. BIRT is licensed under the Eclipse Public License (EPL).”

(Source: https://eclipse.github.io/birt-website/docs/what-is-birt )

The BIRT source code is hosted on GitHub at https://github.com/eclipse/birt

Information on how to contribute can be found here.

The BIRT community can be found on GitHub BIRT Discussions forum

Issues can searched and submitted at https://github.com/eclipse/birt/issues

Tip: It is also worth searching for BIRT-related issues in the old bug tracking system bugzilla