Gradle dependencies does not show all dependencies

A specific jar dependency makes trouble in my Gradle project and I want to figure out the reason. My Gradle project is based on and I use Gradle 4.8. I remove my ~/.gradle directory and run ./gradle assemble. In the output I can see that e.g. the following jars gets downloaded.

Configure project :


Task :generateXtext

How can I figure out the reason why these jars are used? I run gradle dependencies but there is no dependency to the files above.