VS code won't debug a module file with 'cjs' file extension;

I'm using 'cjs' for CommonJS source ('mjs' for es modules).

Using node.js v13.7 w/vscode.

VSCode debugger fails to run the 'cjs' file with:

Cannot launch program... setting the 'outFiles' attribute might help.

Debugger works if I change file extension to 'js'.