It looks like on javaagent versions 1.31+ the -Dotel.javaagent.experimental.extensions is silently ignored, scratching my head as to why I was getting "Unrecognized exporter type google_cloud_trace".
I found that in the readme and code of this repo the are references to both -Dotel.javaagent.experimental.extensions and -Dotel.javaagent.extensions but only the latter one works.
So I think you just need to change all references in examples from otel.javaagent.experimental.extensions to otel.javaagent.extensions and this issue will be fixed.
Thank you.