I'm not sure if this belongs to BlueOcean plugin component, if not please help me move to corresponding place.

After I upgraded my Jenkins to 2.73.2 and BlueOcean to 1.3, it seems that my Github folder automatically pick up any repositories with Jenkinsfile and create pipelines for it, and thus some of my deprecated projects whose pipelines I deleted a long time ago, now appear again and failing. When I create my first pipeline, I didn't use this option, I only create pipeline and select a single repository each time.

Now I want to delete those pipelines, but there are no place to delete it in both classic UI and BlueOcean UI.

I remember in the classic UI, after I go to my github folder and click configure, there is an option for me to specify the repository names that I want to include (I configured it to project-a|project-b|project-c.. before), but now that option was disappeared. When I go under each single repository under my github folder, I expect a button "Delete Repository", but there is no such button either. (check attached screenshot1 and screenshot2)

Another symptom is, when I try to create a new pipeline using BlueOcean UI, all the repositories which I created pipelines before are available to be created again, which is very weird (screenshot3). I tried to create pipeline for a repository whose pipeline was existed to see what happen, and to my surprise, it doesn't appear inside my Github folder like before, but outside of it like a freestyle job. Is this the new structure of BlueOcean?

What am I suppose to do? I only want to create pipelines for my selected projects, I don't wanna recreate any pipelines, there must be a way to convert my pipelines into new structure if there is one. I would prefer a way to stop creating pipelines for my deprecated projects instead. I won't mind those existed repositories to be appeared when create new pipeline, as long as everything is working well.