Polytoria is currently not open source because the current version of Polytoria is based on Unity, and Unity is not open source. Also, due to controversy, there will be Polytoria 2.0, this time based on Godot, and it will be open source. So, in summary, Polytoria is not currently open source, but it will be in the future.

I noticed that games based on Godot don't have to be open source too, but I think it's really cool that the Polytoria Team wants to make it open source. because we could have an editor similar to Turbowarp based on Scratch, but a kind of Turbowarp based on Polytoria's 2.0 editor, so maybe it will be compatible with the community for Roblox models, etc.

I recommend these two articles. The first one gives an overview of 2.0, and the other announces that 2.0 will be open source.

https://blog.polytoria.com/polytoria-2-0-progress-report-1/

https://blog.polytoria.com/polytoria-goes-open-source/