The Hammer is an open source code editor for DataFlex and is a project from VDF-Guidance
Currently (February 2020) The Hammer 3.0 is considered stable and available as Release Candidate 3. It supports all DataFlex versions from 3.x up to DataFlex 2020.
All current development is available and managed via the VDF-Guidance project server:
You can download the latest version from the Files tab down there.
Also note that the documentation is maintained at the project server via the wiki
There's also an unstable branch of the Hammer (The Hammer 4.0) which is targeting to be run under DataFlex 2020.
You can find older content about earlier releases of the Hammer at http://vdf-guidance.com/The_Hammer.asp?Page=THEHAMMER