Re:Defold game engine source now available and free to use f...
by vertex-four on Tuesday May 19, 2020 @10:30AM
(#23235259)
Even ignoring the source then: you can't disassemble the compiled engine, modify it and use your modification commercially, afaict. That's a string.
The engine was released for free with no strings attached - you're free to implement whatever you like using the engine.
The source code was released, with very minor strings attached.