By hitting Ctrl (or Option for Mac), you will be able to see the IDs of tasks, the root, and parent tasks, and attachment icons of tasks if any.
If you are in a grouped mode or filtered mode, you will also see the context (aka breadcrumbs) of tasks.
For example, after you Group by Assignee and press Ctrl (or Option), you will see:
Tip: You will also see the organization the current project belongs to at the top when you toggle Ctrl (or Option).
Without opening the detail panel, by hovering over the icons in Advanced mode, you can see the previews of the task descriptions, subtasks, comments, or attachments.