This page looks like it should be able to provide it, but the download button gives me a 404 error.
I have the photographer’s subscription, with PhotoShop, Lightroom, Bridge, and so on.
hi 
ExtendsScript Toolkit can be found on Adobe CEP Github Page. Sadly this tool does not work on the new Mac OS because this is 32bit app.
Some time ago smart people from Adobe created Extension to Visual Studio Code which allow debug your code.
More info in blog post: