Online editor. Is there an option to printf-debug?

Like in title, is there an option to printf-debug, or any equivalent thereof.

I sprinkled the code with println, only to obtain no output.

Depends on the track. For Kotlin, I don’t think there is currently as I’m not seeing anything in the track docs, or any sort of test case here: kotlin-test-runner/tests at main · exercism/kotlin-test-runner · GitHub