Hi Björn,
I'm looking forward to your findings!
> 1. Is this already the output of "mvn -X" and/or "mvn -e"?
Yes, this is the output of mvn -X (basically, in fact I'm running "java
… org.apache.maven.cli.MavenCli -X").
> 3. Do you have a WIP branch and instructions on how to reproduce this?
You can find the branch "WIP-maven" at
https://gitlab.com/htgoebel/guix.git . To reproduce simply run
git clone https://gitlab.com/htgoebel/guix.git
cd guix
git checkout WIP-maven
./pre-inst-env guix build maven-for-bootstrap