New Relic in Android Studio - newrelic.properties - variants

Okay, so after contacting the support team at New Relic, there is apparently no direct solution for this as of today, although they said they've opened a feature request, and so this problem might be solved soon.

From what I managed to understand, the reason this file is needed is so that the New Relic system can display an un-obfuscated error log when an exception occurs on a production version which has been obfuscated with ProGuard.

The New Relic system, with the help of this file, will upload the ProGuard mapping.txt file to the New Relic servers and associate it with your app according to the specified token. With this, New Relic can un-obfuscate stack traces and display a descriptive stack trace with actual class & method names, rather a, b, c, etc.

As a workaround, I was told that I can forego this file all together, if I upload the mapping file manually.

The mapping file can be found at:

build/outputs/proguard/release/mapping.txt  

In order to manually upload the file, perform the following via command line:

curl -v -F proguard=@"<path_to_mapping.txt>" -H "X-APP-LICENSE-KEY:<APPLICATION_TOKEN>" https://mobile-symbol-upload.newrelic.com/symbol

This must be done for each variant which is being obfuscated with ProGuard (classically, release builds).

Source

Hope this helps someone else.