create a new pipleine using git and https://github.com/apache/maven.git as the URL.
When you are redirected to the pipeline you are told there are no branches containing Jenkinsfiles.
This is so far from the truth
Open a new window in classic and see that branch indexing is happily running and there are branches shown in classic view.
switch between activity/branches and PRs notice that nothing ever updates.
I had to reload the page to see the results.