This is so that for example when one is in the revision settings vtab, the page URL would be /admin/structure/types/add#revisions instead of simply /admin/structure/types/add. It would allow us to point to specific tabs in documentation and also users to be able to refresh their page and have the last selected vtab be remembered.

...BUT can we do that without refreshing the page each time the user switches to a different vtab?

GitHub Link: 
https://github.com/backdrop/backdrop-issues/issues/1537
GitHub Issue #: 
1537