Unclear use of new issue link

When you visit project issues, there's green button New Issue

• https://gitlab.com/gitlab-org/gitlab-ce/issues/new?issue%5Bassignee_id%5D=&issue%5Bmilestone_id%5D=

it always passes empty milestone id and assignee id. why?

i tried to pass values there, seem to be ignored, at least in gitlab-ce edition:

• https://gitlab.example.net/group/project/issues/new?issue%5Bassignee_id%5D=2
• https://gitlab.example.net/group/project/issues/new?issue%5Bassignee_id%5D=glen