Hi Dominik Bartholdi,
I currently do not have very much time to care about Jenkins and I actually didn't work much with the pipeline so far. The pipeline support was added by Benjamin BONNET (see
). About documentation on the pipeline support, please refer to him. I just merged his PR and cleaned up code a little (including upgrade to Jenkins 2). JENKINS-38619
About support of declarative pipeline parameter definition: I currently can only ask You to implement it yourself and file a pull request. I'd try to merge (and release) it ASPA - depending on my current workload in "real-life" projects.
As Gesh Markov gave up maintainership for this plugin and I only have spare time to care about this plugin, I'd be glad about additional maintainers. So, if You like, be my guest . Was the same with me: I needed some features and as Gesh didn't have time (nor environment) to merge my PRs, he suggested/offered me to be added as maintainer/owner.
Maybe not the answer You'd like to read, I'm sorry. But I currently cannot offer much more here...