Why uses the "Corona Warn App" so many Singletons?

I'm interested in good software architecture and looking for good examples to learn it and how to use Kotlin in a good way. I had a look on the "Corona Warn App", the Covid 19 Application in Germany which is Open Source. It were developed by stated as very good software engineers from SAP and Telekom. As reading thru I stumpled over many Singletons which are considered as bad practice. Of course it depends on the use case, but arguments like bad testability are remianing. The CWA consists of really really many Singletons.

Am I missing something which is different if you use Kotlins object, is this really "bad code" or is this a good example for using Singletons?

You can find the source code here: https://github.com/corona-warn-app/cwa-app-android

Edit: I'm not sure why this post gets downvoted. It would be nice if you could leave a short commentary which explains why you downvoted and why this is not a useful question.