Physical presence of the vie file is not mandatory. Even if the file for the view doesn't exist, you can still extend it using the api - elgg_extend_view()
If you want to remove the group file widget then
These links may help you
Thank you very much for your reply, Team webgalli.
it works when using elgg_push_breadcrumb($group->name); twice which is a little bit weird as you said. Could be a little bug of elgg. Thanks for your reply.
Could be a little bug of elgg
I have encountered in Elgg 1.9 too
Not a bug, it's default behavior. Previous versions used to show link-less endpoint breadcrumbs but the core team voted in favor of removing them.