Not sure, but https://exodus-privacy.eu.org/en/ lets you check any app for the presence of trackers. Is that relevant?

not sure what section you mean, but check out jadx: https://github.com/skylot/jadx

Experience in java is recommended.

You can look at some of the documentation to see how at least some of it works.

https://developers.google.com/google-ads/api/docs/start

And here’s Matomos analytics

https://matomo.org/guide/apis/

Is that what you’re looking for?

Generally speaking it’s not possible to strictly deduce code from its output.

But you can establish a pretty good guess by converting log messages into regexes then using those regexes in github code search.