Issue:Can't find the defination of "new_project_issue_path", “new_issue_path" and "edit_issue_path"

I want to know how it works inside the select tag "status_id" in the "create new issue". However, when I tried to follow it, I couldn't find the defination of "new_project_issue_path", "new_issue_path" and "edit_issue_path".

Is there anyone who can help me? T_T

Thanks a lot.