If you are open an iModel there is no name written of it in the headline.
If you have similar iModels (as I do) sometimes you get confused which one is opened.
It would be a benefit if the headline would show the opened iModel name.
For exmple: ProjectWise 365 \ Project name \ iModel name
Thanks!
This was shipped a while ago in the viewer. It's not a "breadcrumb trail" per se, but the current iModel is displayed in a drop-down in the top right corner allowing you to switch to anotehr iModel.