For the GSoC project   gitlab-branch-source-plugin the student is requesting a new repo be created titled "gitlab-branch-plugin

Detailed reasoning for this is here: 

2) I read the documentation of SCM API and Branch API Plugins to understand the classes needs to be implemented in GitLab Branch Source Plugin. Based on which I prepared the design document. This design document will be improved throughout the course of development. Will add apis, workflow, issues etc to it.

3) I have been studing the codebases of ArgelBargel's GitLab Branch Source Plugin, GitHub Branch Source Plugin and Gitea Plugin. My takeaway was GitLab BS has been implemented in a way that is not very different from the other Branch Source Plugins in terms of the underlying APIs implementation but still exists some differences that cannot be ignored. For example,

i) The class names are different and many code refractories has been done so it creates a difficulty in implementing the same logic while extending the plugin. Like SCMSource has been broken down to other sub classes , SCMHeadCategory has some different implementation, SCMFileSystem is not implemented, APIs implementation also needs to be changed and the list goes on..

ii) The conclusion I have come to is that it would be rather lesser amount of work for me if I had to implement a new GitLab Branch Source Plugin which will be heavily inspired from Gitea Plugin (as suggested by Robert Sandall in mailing list) and also some inspiration will be taken from GitLab Branch Source and GitHub Branch Source Plugins.

iii) I will send my complete list of reasons not to develop the existing GitLab Branch Source Plugin.