It's on GitHub in case you'd like to answer that question by source inspection. I'm not familiar with Android so I can't do so for you, sorry:

https://mtransitapps.github.io/

Apparently yes. The gradle file of the project does include it.

Why could this be related to this issue?

looks like it? https://github.com/mtransitapps/mtransit-for-android/search?...