OpenJSCAD is an opensource software similar to OpenSCAd in many ways, but not compatable. The OpenSCAD user will find it fairy easy to pick up OpenJSCAD.
The main difference is OpenJSCAD uses JavaScript style coding. ( It may be entirely JavaScript, I have yet to learn that. )
OpenJSCAD is a CSG style CAD so OpenSCAD users will be quite comfortable with a similar workflow.
You can try out OpenJSCAD by visiting the website: https://openjscad.org/
If you would like to run your own version, hit up github here: https://github.com/jscad/OpenJSCAD.org