I’m not sure what to call these, however Notion allows you to add drop down filter parameters to a view, so that if you, say, have a Context property on tasks, there can be a dropdown that allow you to see All, or specific contexts, without creating a separate view.
Changes to these are not saved unless the tis explicitly chosen.
Real World Use-Cases
There are so many. Wanting to see my tasks with “Errands” as their Context.
There’s probably a cleaner way to add this than what Notion does.